485BPOS

As filed with the Securities and Exchange Commission on October 16, 2015
File Nos. 333-76651, 811-09301

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	o
Post-Effective Amendment No. 88	x
and/or
REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT	x
OF 1940
Amendment No. 91	x
(Check appropriate box or boxes)

TIAA-CREF Funds
(Exact Name of Registrant as Specified in Charter)

730 Third Avenue
New York, New York 10017-3206
(Address of Principal Executive Offices) (Zip Code)
Registrant’s Telephone Number, including Area Code: (800) 842-2733

Terry H. Lin, Esq.
TIAA-CREF Funds
730Third Avenue
New York, N.Y 10017-3206

(Name and Address of Agent for Service)

Copy to:
Jeffrey S. Puretz, Esq.
Dechert LLP
1900 K Street, N.W.
Washington, D.C. 20006

Approximate Date of Proposed Public Offering:
As soon as practicable after effectiveness of the Registration Statement.

It is proposed that this filing will become effective (check appropriate box):

x Immediately upon filing pursuant to paragraph (b)

o On (date) pursuant to paragraph (b)

o 60 days after filing pursuant to paragraph (a)(1)

o 75 days after filing pursuant to paragraph (a)(2)

o On (date) pursuant to paragraph (a)(1)

o On (date) pursuant to paragraph (a)(2) of rule 485

If appropriate, check the following box:

o This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Explanatory Note

This post-effective amendment on Form 485BPOS is being submitted for the sole purpose of furnishing, in Exhibit 101, XBRL Interactive Data for the related official 485BPOS filing which was submitted to the Commission on September 25, 2015.

No other changes have been made to this Form 485BPOS. This Form 485BPOS does not reflect events that may have occurred subsequent to the original filing date, and does not modify or update any related disclosures made in the related official Form 485BPOS.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, TIAA-CREF Funds certifies that it meets all the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of New York, and State of New York on the 16 day of October, 2015.

TIAA-CREF FUNDS
By:	/s/ Robert G. Leary
Name:	Robert G. Leary
Title:	President and Principal Executive Officer

Pursuant to the requirements of the Securities Act, this registration statement has been signed below by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/s/ Robert G. Leary	President and Principal Executive Officer	October 16, 2015
Robert G. Leary	(Principal Executive Officer)
/s/ Phillip G. Goff	Principal Financial Officer,	October 16, 2015
Phillip G. Goff	Principal Accounting Officer and Treasurer
	(Principal Financial and Accounting Officer)

SIGNATURE OF TRUSTEE	DATE	SIGNATURE OF TRUSTEE	DATE
*	October 16, 2015	*	October 16, 2015
Forrest Berkley		Thomas J. Kenny
*	October 16, 2015	*	October 16, 2015
Nancy A. Eckl		Bridget A. Macaskill
*	October 16, 2015	*	October 16, 2015
Michael A. Forrester		James M. Poterba
*	October 16, 2015	*	October 16, 2015
Howell E. Jackson		Maceo K. Sloan
*	October 16, 2015	*	October 16, 2015
Nancy L. Jacobs		Laura T. Starks
/s/ Rachael M. Zufall	October 16, 2015
Rachael M. Zufall
as attorney-in-fact

* Signed by Rachael M. Zufall pursuant to powers of attorney previously filed with the Securities and Exchange Commission.

EXHIBIT LIST

101.	INS XBRL Instance Document
101.	SCH XBRL Taxonomy Extension Schema
101.	DEF XBRL Taxonomy Extension Definition Linkbase
101.	LAB XBRL Taxonomy Extension Label Linkbase
101.	PRE XBRL Taxonomy Extension Presentation Linkbase

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TIAA-CREF Lifecycle Index 2025 Fund

TIAA-CREF Lifecycle Index 2025 Fund

Investment objective

The Lifecycle Index 2025 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2025 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2025 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.09%	0.09%	0.09%
Total Annual Fund Operating Expenses		0.52%	0.37%	0.22%
Waivers and Expense Reimbursements	[3],[4]	(0.15%)	(0.10%)	(0.10%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2025 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	152	109	61
5 Years	276	198	114
10 Years	$ 638	$ 458	$ 270

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2025. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 66.00% of the Fund’s assets to equity Underlying Funds and 34.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2025 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2032 to 2035. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 45.08%; International Equity: 19.32%; Fixed-Income: 30.80%; Short-Term Fixed-Income: 2.40%; and Inflation-Protected Assets: 2.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	66.01%	U.S. Equity	46.51%	ŸEquity Index Fund	46.51%
		International Equity	19.50%	ŸInternational Equity Index Fund	14.99%
				ŸEmerging Markets Equity Index Fund	4.51%
FIXED-INCOME	33.99%	Fixed-Income	32.01%	ŸBond Index Fund	32.01%
		Inflation-Protected Assets	1.98%	ŸInflation-Linked Bond Fund	1.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2025 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.93%.

Best quarter: 10.18%, for the quarter ended September 30, 2010. Worst quarter: -11.34%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2025 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.39%	9.82%	10.06%		Sep. 30, 2009
Institutional Class		6.62%	10.09%	10.33%		Sep. 30, 2009
Premier Class		6.41%	9.92%	10.16%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.70%	9.31%	9.56%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.87%	7.69%	7.91%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2025 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.88%	10.26%	10.53%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.07%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.28% of average daily net assets for Retirement Class shares; (ii) 0.18% of average daily net assets for Premier Class shares; and (iii) 0.03% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2025 Fund Composite Index consisted of: 46.8% Russell 3000 Index; 31.4% Barclays U.S. Aggregate Bond Index; 20.0% MSCI EAFE + Emerging Markets Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifestyle Growth Fund

TIAA-CREF Lifestyle Growth Fund

Investment objective

The Fund seeks long-term growth of capital with some current income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifestyle Growth Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifestyle Growth Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees		0.25%		0.15%
Other Expenses		0.24%	0.45%	0.21%	0.21%
Acquired Fund Fees and Expenses	[1]	0.43%	0.43%	0.43%	0.43%
Total Annual Fund Operating Expenses		1.02%	0.98%	0.89%	0.74%
Waivers and Expense Reimbursements	[2]	(0.20%)	(0.20%)	(0.21%)	(0.21%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.82%	0.78%	0.68%	0.53%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifestyle Growth Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 84	$ 80	$ 69	$ 54
3 Years	305	292	263	215
5 Years	544	522	472	391
10 Years	$ 1,230	$ 1,183	$ 1,077	$ 899

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term growth of capital with some current income through a relatively stable asset allocation strategy targeting a growth-oriented risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 80% of the Fund’s assets in equity Underlying Funds and (2) approximately 20% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	80.04%	U.S. Equity	55.26%	ŸLarge-Cap Growth Fund	14.41%
				ŸLarge-Cap Value Fund	13.36%
				ŸGrowth & Income Fund	11.85%
				ŸEnhanced Large-Cap Growth Index Fund	5.10%
				ŸEnhanced Large-Cap Value Index Fund	4.72%
				ŸSmall-Cap Equity Fund	4.34%
				ŸMid-Cap Growth Fund	0.79%
				ŸMid-Cap Value Fund	0.69%
		International Equity	24.78%	ŸInternational Equity Fund	8.17%
				ŸInternational Opportunities Fund	5.93%
				ŸEnhanced International Equity Index Fund	5.06%
				ŸEmerging Markets Equity Fund	4.43%
				ŸGlobal Natural Resources Fund	1.19%
FIXED-INCOME	19.96%	Fixed-Income	19.96%	ŸBond Plus Fund	18.93%
				ŸHigh-Yield Fund	1.03%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a higher percentage of equity Underlying Funds, Equity Underlying Fund Risks are expected to predominate.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Growth Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.02%.

Best quarter: 11.87%, for the quarter ended March 31, 2012. Worst quarter: -3.87%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifestyle Growth Fund		One Year	Since Inception		Inception Date
Institutional Class		4.73%	14.24%		Dec. 09, 2011
Retail Class		4.42%	13.90%		Dec. 09, 2011
Retirement Class		4.43%	13.95%		Dec. 09, 2011
Premier Class		4.58%	14.07%		Dec. 09, 2011
After Taxes on Distributions | Institutional Class		3.32%	13.02%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.26%	10.88%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	20.13%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	2.86%	[1]
Lifestyle Growth Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.18%	13.79%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Growth Fund Composite Index consisted of: 56.0% Russell 3000 Index; 24.0% MSCI All Country World Index ex USA; and 20.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifestyle Income Fund

TIAA-CREF Lifestyle Income Fund

Investment objective

The Fund seeks current income with some capital appreciation.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifestyle Income Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifestyle Income Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees		0.25%		0.15%
Other Expenses		0.27%	0.49%	0.25%	0.25%
Acquired Fund Fees and Expenses	[1]	0.33%	0.33%	0.33%	0.33%
Total Annual Fund Operating Expenses		0.95%	0.92%	0.83%	0.68%
Waivers and Expense Reimbursements	[2]	(0.24%)	(0.24%)	(0.25%)	(0.25%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.71%	0.68%	0.58%	0.43%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifestyle Income Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 73	$ 69	$ 59	$ 44
3 Years	279	269	240	192
5 Years	502	486	436	354
10 Years	$ 1,144	$ 1,109	$ 1,002	$ 823

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking current income with some capital appreciation through a relatively stable asset allocation strategy targeting an income-oriented and conservative risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 20% of the Fund’s assets in equity Underlying Funds and (2) approximately 80% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	20.15%	U.S. Equity	13.62%	ŸLarge-Cap Growth Fund	3.63%
				ŸLarge-Cap Value Fund	3.36%
				ŸGrowth & Income Fund	2.98%
				ŸEnhanced Large-Cap Growth Index Fund	1.21%
				ŸEnhanced Large-Cap Value Index Fund	1.11%
				ŸSmall-Cap Equity Fund	1.10%
				ŸMid-Cap Growth Fund	0.13%
				ŸMid-Cap Value Fund	0.10%
		International Equity	6.53%	ŸInternational Equity Fund	2.20%
				ŸInternational Opportunities Fund	1.49%
				ŸEnhanced International Equity Index Fund	1.28%
				ŸEmerging Markets Equity Fund	1.26%
				ŸGlobal Natural Resources Fund	0.30%
FIXED-INCOME	79.85%	Fixed-Income	39.89%	ŸBond Plus Fund	19.88%
				ŸBond Fund	18.99%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	39.96%	ŸShort-Term Bond Fund	39.96%
				ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a higher percentage of fixed-income Underlying Funds, Fixed-Income Underlying Fund Risks are expected to predominate.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income;

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available; and

· Fixed-income foreign investment risk—Investment in fixed-income securities or financial instruments of foreign issuers involves increased risks due to adverse issuer, political, regulatory, currency, market or economic developments. These developments may impact the ability of a foreign debt issuer to make timely and ultimate payments on its debt obligations to the Fund or impair the Fund’s ability to enforce its rights against the foreign debt issuer. These risks are heightened in emerging or developing markets.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets; and

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Income Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.43%.

Best quarter: 3.94%, for the quarter ended March 31, 2012. Worst quarter: -1.39%, for the quarter ended June 30, 2013.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifestyle Income Fund		One Year	Since Inception		Inception Date
Institutional Class		3.54%	5.64%		Dec. 09, 2011
Retail Class		3.18%	5.34%		Dec. 09, 2011
Retirement Class		3.30%	5.38%		Dec. 09, 2011
Premier Class		3.40%	5.49%		Dec. 09, 2011
After Taxes on Distributions | Institutional Class		2.44%	4.57%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		2.20%	3.98%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	2.86%	[1]
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	20.13%	[1]
Lifestyle Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	4.20%	4.83%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 40.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; 14.0% Russell 3000 Index; and 6.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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Label

Element

Value

TIAA-CREF Lifecycle 2055 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2055 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2055 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

9.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2055.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2055 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2062 to 2065. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.99%	U.S. Equity	61.97%	ŸLarge-Cap Growth Fund	12.07%
				ŸEnhanced Large-Cap Growth Index Fund	11.78%
				ŸLarge-Cap Value Fund	11.20%
				ŸEnhanced Large-Cap Value Index Fund	10.94%
				ŸGrowth & Income Fund	9.93%
				ŸSmall-Cap Equity Fund	4.90%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.53%
		International Equity	28.02%	ŸInternational Equity Fund	7.84%
				ŸEnhanced International Equity Index Fund	7.23%
				ŸInternational Opportunities Fund	6.65%
				ŸEmerging Markets Equity Fund	4.97%
				ŸGlobal Natural Resources Fund	1.33%
FIXED-INCOME	10.01%	Fixed-Income	10.00%	ŸHigh-Yield Fund	5.00%
				ŸBond Plus Fund	4.02%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle 2055 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2055 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.16%.

Bar Chart Closing [Text Block]

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Best quarter: 12.82%, for the quarter ended March 31, 2012. Worst quarter: -4.50%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.16%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.82%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(4.50%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2055 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

13.91%

^[1]

TIAA-CREF Lifecycle 2055 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

3.81%

^[1]

TIAA-CREF Lifecycle 2055 Fund | Lifecycle 2055 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.30%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

9.81%

^[1],[2]

TIAA-CREF Lifecycle 2055 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.36%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.95%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.26%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

277

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

500

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,143

Annual Return 2012

rr_AnnualReturn2012

17.30%

Annual Return 2013

rr_AnnualReturn2013

25.92%

Annual Return 2014

rr_AnnualReturn2014

4.37%

One Year

rr_AverageAnnualReturnYear01

4.37%

Since Inception

rr_AverageAnnualReturnSinceInception

8.80%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

TIAA-CREF Lifecycle 2055 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.04%

Since Inception

rr_AverageAnnualReturnSinceInception

7.78%

TIAA-CREF Lifecycle 2055 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.05%

Since Inception

rr_AverageAnnualReturnSinceInception

6.64%

TIAA-CREF Lifecycle 2055 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.11%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.80%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.59%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 60

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

234

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

424

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 970

One Year

rr_AverageAnnualReturnYear01

4.39%

Since Inception

rr_AverageAnnualReturnSinceInception

8.89%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

TIAA-CREF Lifecycle 2055 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.11%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.65%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.44%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 45

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

187

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

341

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 791

One Year

rr_AverageAnnualReturnYear01

4.58%

Since Inception

rr_AverageAnnualReturnSinceInception

9.07%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2055 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2015 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2015 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2015 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

12.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2015. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 50.00% of the Fund’s assets to equity Underlying Funds and 50.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2015 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2022 to 2025. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 34.30%; International Equity: 14.70%; Fixed-Income: 38.20%; Short-Term Fixed-Income: 6.40%; and Inflation-Protected Assets: 6.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	50.15%	U.S. Equity	35.29%	ŸEquity Index Fund	35.29%
		International Equity	14.86%	ŸInternational Equity Index Fund	11.42%
				ŸEmerging Markets Equity Index Fund	3.44%
FIXED-INCOME	49.85%	Fixed-Income	43.92%	ŸBond Index Fund	43.92%
		Inflation-Protected Assets	5.93%	ŸInflation-Linked Bond Fund	5.93%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2015 Fund Composite Index consisted of: 43.4% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000® Index; 15.2% MSCI EAFE + Emerging Markets Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2015 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.42%.

Bar Chart Closing [Text Block]

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Best quarter: 8.63%, for the quarter ended September 30, 2010. Worst quarter: -8.09%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.42%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

8.63%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(8.09%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2015 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2015 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2015 Fund | Lifecycle Index 2015 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.59%

^[2]

Five Years

rr_AverageAnnualReturnYear05

8.99%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

9.17%

^[1],[2]

TIAA-CREF Lifecycle Index 2015 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.29%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.10%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.54%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

156

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

285

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 661

Annual Return 2010

rr_AnnualReturn2010

11.03%

Annual Return 2011

rr_AnnualReturn2011

2.28%

Annual Return 2012

rr_AnnualReturn2012

11.07%

Annual Return 2013

rr_AnnualReturn2013

12.54%

Annual Return 2014

rr_AnnualReturn2014

6.07%

One Year

rr_AverageAnnualReturnYear01

6.07%

Five Years

rr_AverageAnnualReturnYear05

8.53%

Since Inception

rr_AverageAnnualReturnSinceInception

8.69%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2015 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.33%

Five Years

rr_AverageAnnualReturnYear05

7.95%

Since Inception

rr_AverageAnnualReturnSinceInception

8.12%

TIAA-CREF Lifecycle Index 2015 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.63%

Five Years

rr_AverageAnnualReturnYear05

6.57%

Since Inception

rr_AverageAnnualReturnSinceInception

6.72%

TIAA-CREF Lifecycle Index 2015 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.04%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.10%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.39%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

113

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

207

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 481

One Year

rr_AverageAnnualReturnYear01

6.19%

Five Years

rr_AverageAnnualReturnYear05

8.64%

Since Inception

rr_AverageAnnualReturnSinceInception

8.80%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2015 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.04%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.10%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.24%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

65

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

123

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 294

One Year

rr_AverageAnnualReturnYear01

6.40%

Five Years

rr_AverageAnnualReturnYear05

8.81%

Since Inception

rr_AverageAnnualReturnSinceInception

8.97%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2015 Fund Composite Index consisted of: 43.4% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000 Index; 15.2% MSCI EAFE + Emerging Markets Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.08%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.27% of average daily net assets for Retirement Class shares; (ii) 0.17% of average daily net assets for Premier Class shares; and (iii) 0.02% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle 2060 Fund

TIAA-CREF Lifecycle 2060 Fund

Investment objective

The Lifecycle 2060 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2060 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2060 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		1.84%	1.57%	1.54%
Acquired Fund Fees and Expenses	[2]	0.44%	0.44%	0.44%
Total Annual Fund Operating Expenses		2.43%	2.26%	2.08%
Waivers and Expense Reimbursements	[3],[4]	(1.74%)	(1.67%)	(1.64%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.69%	0.59%	0.44%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2060 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 70	$ 60	$ 45
3 Years	591	545	493
5 Years	1,138	1,057	967
10 Years	$ 2,633	$ 2,465	$ 2,279

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal period between September 26, 2014 (inception date) and May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2060.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2060 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2067 to 2070. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s target asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, for June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.13%	U.S. Equity	62.29%	ŸLarge-Cap Growth Fund	12.19%
				ŸEnhanced Large-Cap Growth Index Fund	11.82%
				ŸLarge-Cap Value Fund	11.25%
				ŸEnhanced Large-Cap Value Index Fund	11.01%
				ŸGrowth & Income Fund	9.98%
				ŸSmall-Cap Equity Fund	4.88%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.54%
		International Equity	27.84%	ŸInternational Equity Fund	7.79%
				ŸEnhanced International Equity Index Fund	7.11%
				ŸInternational Opportunities Fund	6.67%
				ŸEmerging Markets Equity Fund	4.92%
				ŸGlobal Natural Resources Fund	1.35%
FIXED-INCOME	9.87%	Fixed-Income	9.87%	ŸHigh-Yield Fund	4.97%
				ŸBond Plus Fund	3.92%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2025 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2025 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2025 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

6.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2025. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 66.00% of the Fund’s assets to equity Underlying Funds and 34.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2025 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2032 to 2035. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 45.08%; International Equity: 19.32%; Fixed-Income: 30.80%; Short-Term Fixed-Income: 2.40%; and Inflation-Protected Assets: 2.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	66.01%	U.S. Equity	46.51%	ŸEquity Index Fund	46.51%
		International Equity	19.50%	ŸInternational Equity Index Fund	14.99%
				ŸEmerging Markets Equity Index Fund	4.51%
FIXED-INCOME	33.99%	Fixed-Income	32.01%	ŸBond Index Fund	32.01%
		Inflation-Protected Assets	1.98%	ŸInflation-Linked Bond Fund	1.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2025 Fund Composite Index consisted of: 46.8% Russell 3000® Index; 31.4% Barclays U.S. Aggregate Bond Index; 20.0% MSCI EAFE + Emerging Markets Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2025 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.93%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 10.18%, for the quarter ended September 30, 2010. Worst quarter: -11.34%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.93%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

10.18%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(11.34%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2025 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2025 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2025 Fund | Lifecycle Index 2025 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.88%

^[2]

Five Years

rr_AverageAnnualReturnYear05

10.26%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

10.53%

^[1],[2]

TIAA-CREF Lifecycle Index 2025 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.52%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

152

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

276

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 638

Annual Return 2010

rr_AnnualReturn2010

12.31%

Annual Return 2011

rr_AnnualReturn2011

0.38%

Annual Return 2012

rr_AnnualReturn2012

13.00%

Annual Return 2013

rr_AnnualReturn2013

17.87%

Annual Return 2014

rr_AnnualReturn2014

6.39%

One Year

rr_AverageAnnualReturnYear01

6.39%

Five Years

rr_AverageAnnualReturnYear05

9.82%

Since Inception

rr_AverageAnnualReturnSinceInception

10.06%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2025 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.70%

Five Years

rr_AverageAnnualReturnYear05

9.31%

Since Inception

rr_AverageAnnualReturnSinceInception

9.56%

TIAA-CREF Lifecycle Index 2025 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.87%

Five Years

rr_AverageAnnualReturnYear05

7.69%

Since Inception

rr_AverageAnnualReturnSinceInception

7.91%

TIAA-CREF Lifecycle Index 2025 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.37%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

109

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

198

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 458

One Year

rr_AverageAnnualReturnYear01

6.41%

Five Years

rr_AverageAnnualReturnYear05

9.92%

Since Inception

rr_AverageAnnualReturnSinceInception

10.16%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2025 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.22%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

61

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

114

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 270

One Year

rr_AverageAnnualReturnYear01

6.62%

Five Years

rr_AverageAnnualReturnYear05

10.09%

Since Inception

rr_AverageAnnualReturnSinceInception

10.33%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2025 Fund Composite Index consisted of: 46.8% Russell 3000 Index; 31.4% Barclays U.S. Aggregate Bond Index; 20.0% MSCI EAFE + Emerging Markets Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.07%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.28% of average daily net assets for Retirement Class shares; (ii) 0.18% of average daily net assets for Premier Class shares; and (iii) 0.03% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle Index 2040 Fund

TIAA-CREF Lifecycle Index 2040 Fund

Investment objective

The Lifecycle Index 2040 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2040 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2040 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		0.50%	0.35%	0.20%
Waivers and Expense Reimbursements	[3],[4]	(0.13%)	(0.08%)	(0.08%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2040 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	147	104	56
5 Years	267	188	105
10 Years	$ 616	$ 435	$ 247

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2040. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2040 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2047 to 2050. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 61.88%; International Equity: 26.52%; Fixed-Income: 11.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.98%	U.S. Equity	63.30%	ŸEquity Index Fund	63.30%
		International Equity	26.68%	ŸInternational Equity Index Fund	20.50%
				ŸEmerging Markets Equity Index Fund	6.18%
FIXED-INCOME	10.02%	Fixed-Income	10.02%	ŸBond Index Fund	10.02%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2040 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.59%.

Best quarter: 11.87%, for the quarter ended September 30, 2010. Worst quarter: -14.82%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2040 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.56%	11.38%	11.70%		Sep. 30, 2009
Institutional Class		6.85%	11.65%	11.97%		Sep. 30, 2009
Premier Class		6.65%	11.47%	11.79%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.92%	10.90%	11.23%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		4.05%	9.02%	9.31%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2040 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.18%	11.84%	12.17%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2040 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2040 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2040 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2040 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

11.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2040.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2040 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2047 to 2050. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 61.88%; International Equity: 26.52%; Fixed-Income: 11.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.05%	U.S. Equity	62.18%	ŸLarge-Cap Growth Fund	12.15%
				ŸEnhanced Large-Cap Growth Index Fund	11.79%
				ŸLarge-Cap Value Fund	11.23%
				ŸEnhanced Large-Cap Value Index Fund	10.98%
				ŸGrowth & Income Fund	9.98%
				ŸSmall-Cap Equity Fund	4.91%
				ŸMid-Cap Growth Fund	0.61%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.87%	ŸInternational Equity Fund	7.79%
				ŸEnhanced International Equity Index Fund	7.08%
				ŸInternational Opportunities Fund	6.71%
				ŸEmerging Markets Equity Fund	4.94%
				ŸGlobal Natural Resources Fund	1.35%
FIXED-INCOME	9.95%	Fixed-Income	9.94%	ŸHigh-Yield Fund	4.98%
				ŸBond Plus Fund	3.98%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle 2040 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2040 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.21%.

Bar Chart Closing [Text Block]

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Best quarter: 17.54%, for the quarter ended June 30, 2009. Worst quarter: -20.27%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.21%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.54%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.27%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2040 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2040 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2040 Fund | Lifecycle 2040 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.30%

^[1]

Five Years

rr_AverageAnnualReturnYear05

11.85%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

6.50%

^[1]

TIAA-CREF Lifecycle 2040 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.86%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

257

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

460

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,045

Annual Return 2005

rr_AnnualReturn2005

5.30%

Annual Return 2006

rr_AnnualReturn2006

13.12%

Annual Return 2007

rr_AnnualReturn2007

10.28%

Annual Return 2008

rr_AnnualReturn2008

(38.14%)

Annual Return 2009

rr_AnnualReturn2009

28.39%

Annual Return 2010

rr_AnnualReturn2010

15.21%

Annual Return 2011

rr_AnnualReturn2011

(3.87%)

Annual Return 2012

rr_AnnualReturn2012

17.37%

Annual Return 2013

rr_AnnualReturn2013

25.85%

Annual Return 2014

rr_AnnualReturn2014

4.38%

One Year

rr_AverageAnnualReturnYear01

4.38%

Five Years

rr_AverageAnnualReturnYear05

11.30%

Ten Years

rr_AverageAnnualReturnYear10

5.94%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2040 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.63%

Five Years

rr_AverageAnnualReturnYear05

10.14%

Ten Years

rr_AverageAnnualReturnYear10

5.08%

TIAA-CREF Lifecycle 2040 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.47%

Five Years

rr_AverageAnnualReturnYear05

8.83%

Ten Years

rr_AverageAnnualReturnYear10

4.59%

TIAA-CREF Lifecycle 2040 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.71%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.59%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 60

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

215

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

383

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 871

One Year

rr_AverageAnnualReturnYear01

4.49%

Five Years

rr_AverageAnnualReturnYear05

11.42%

Ten Years

rr_AverageAnnualReturnYear10

6.01%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2040 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.56%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.44%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 45

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

167

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

301

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 690

One Year

rr_AverageAnnualReturnYear01

4.63%

Five Years

rr_AverageAnnualReturnYear05

11.58%

Ten Years

rr_AverageAnnualReturnYear10

6.16%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2040 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2050 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2050 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2050 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 7% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

7.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2050.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2050 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2057 to 2060. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.02%	U.S. Equity	62.05%	ŸLarge-Cap Growth Fund	12.13%
				ŸEnhanced Large-Cap Growth Index Fund	11.78%
				ŸLarge-Cap Value Fund	11.20%
				ŸEnhanced Large-Cap Value Index Fund	10.94%
				ŸGrowth & Income Fund	9.96%
				ŸSmall-Cap Equity Fund	4.90%
				ŸMid-Cap Growth Fund	0.61%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.97%	ŸInternational Equity Fund	7.83%
				ŸEnhanced International Equity Index Fund	7.18%
				ŸInternational Opportunities Fund	6.64%
				ŸEmerging Markets Equity Fund	4.98%
				ŸGlobal Natural Resources Fund	1.34%
FIXED-INCOME	9.98%	Fixed-Income	9.98%	ŸHigh-Yield Fund	4.98%
				ŸBond Plus Fund	4.02%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle 2050 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2050 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.20%.

Bar Chart Closing [Text Block]

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Best quarter: 17.30%, for the quarter ended June 30, 2009. Worst quarter: -21.79%, for the quarter ended December 31, 2008.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

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Jun. 30, 2015

Bar Chart, Year to Date Return

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4.20%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

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Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.30%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

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(21.79%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

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AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2050 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

7.35%

^[1]

TIAA-CREF Lifecycle 2050 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.76%

^[1]

TIAA-CREF Lifecycle 2050 Fund | Lifecycle 2050 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

7.30%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.85%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

5.15%

^[1],[2]

TIAA-CREF Lifecycle 2050 Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

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none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

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none

Maximum Account Fee

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none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

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0.05%

^[3]

Other Expenses

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0.28%

Acquired Fund Fees and Expenses

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0.44%

^[4]

Total Annual Fund Operating Expenses

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0.87%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

260

Expense Example, with Redemption, 5 Years

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465

Expense Example, with Redemption, 10 Years

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$ 1,056

Annual Return 2008

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(38.94%)

Annual Return 2009

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28.05%

Annual Return 2010

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15.03%

Annual Return 2011

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(3.80%)

Annual Return 2012

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17.24%

Annual Return 2013

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25.98%

Annual Return 2014

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4.26%

One Year

rr_AverageAnnualReturnYear01

4.26%

Five Years

rr_AverageAnnualReturnYear05

11.25%

Since Inception

rr_AverageAnnualReturnSinceInception

4.10%

Inception Date

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Nov. 30, 2007

TIAA-CREF Lifecycle 2050 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

2.82%

Five Years

rr_AverageAnnualReturnYear05

10.33%

Since Inception

rr_AverageAnnualReturnSinceInception

3.28%

TIAA-CREF Lifecycle 2050 Fund | Premier Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

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none

Maximum Deferred Sales Charge

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none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

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none

Maximum Account Fee

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none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

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0.15%

^[3]

Other Expenses

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0.03%

Acquired Fund Fees and Expenses

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0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.72%

Waivers and Expense Reimbursements

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(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.59%

Expense Example, with Redemption, 1 Year

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$ 60

Expense Example, with Redemption, 3 Years

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217

Expense Example, with Redemption, 5 Years

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388

Expense Example, with Redemption, 10 Years

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$ 882

One Year

rr_AverageAnnualReturnYear01

4.47%

Five Years

rr_AverageAnnualReturnYear05

11.37%

Since Inception

rr_AverageAnnualReturnSinceInception

4.18%

^[7]

Inception Date

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Sep. 30, 2009

TIAA-CREF Lifecycle 2050 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

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^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

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0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.57%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.44%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 45

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

170

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

305

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 701

One Year

rr_AverageAnnualReturnYear01

4.59%

Five Years

rr_AverageAnnualReturnYear05

11.53%

Since Inception

rr_AverageAnnualReturnSinceInception

4.37%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

TIAA-CREF Lifecycle 2050 Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.07%

Five Years

rr_AverageAnnualReturnYear05

8.76%

Since Inception

rr_AverageAnnualReturnSinceInception

3.00%

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2050 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[7] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

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TIAA-CREF Managed Allocation Fund

TIAA-CREF Managed Allocation Fund

Investment objective

The Fund seeks favorable returns that reflect the broad investment performance of the financial markets through capital appreciation and investment income. The Fund will pursue this goal through a “fund of funds” approach, whereby the Fund will make investments primarily in other mutual funds.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Managed Allocation Fund - USD ($)	Retail Class	Retirement Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Managed Allocation Fund		Retail Class	Retirement Class	Institutional Class
Distribution (Rule 12b-1) Fees		0.25%
Other Expenses		0.07%	0.28%	0.03%
Acquired Fund Fees and Expenses	[1]	0.40%	0.40%	0.40%
Total Annual Fund Operating Expenses		0.72%	0.68%	0.43%
Waivers and Expense Reimbursements	[2]	(0.07%)	(0.03%)	(0.03%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.65%	0.65%	0.40%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Managed Allocation Fund - USD ($)	Retail Class	Retirement Class	Institutional Class
1 Year	$ 66	$ 66	$ 41
3 Years	223	215	135
5 Years	394	376	238
10 Years	$ 888	$ 844	$ 539

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy and will generally seek to meet its investment objective by investing: (1) approximately 60.00% of its assets in equity Underlying Funds including up to 5% of its assets in real estate Underlying Funds; and (2) approximately 40.00% of its assets in fixed-income Underlying Funds (“target allocations”).

The Fund currently intends to invest in the following equity Underlying Funds: Growth & Income Fund, International Equity Fund, International Opportunities Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Emerging Markets Equity Fund, Small-Cap Equity Fund, Enhanced International Equity Index Fund, Enhanced Large-Cap Growth Index Fund, Enhanced Large-Cap Value Index Fund, Global Natural Resources Fund and Real Estate Securities Fund.

The Fund currently intends to invest in the following fixed-income Underlying Funds: Bond Plus Fund, Short-Term Bond Fund, High-Yield Fund and Inflation-Linked Bond Fund.

As a result of its investments in the Underlying Funds, the Managed Allocation Fund’s returns will reflect investments in a mix of domestic stocks of companies of all sizes, foreign equities, real estate securities and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the foreign and domestic equity markets, as well as overall financial and economic conditions. If the portfolio managers believe that the relative attractiveness of the markets in which the equity and fixed-income funds are invested changes, they can adjust the percentage of investments in these Underlying Funds up or down by up to ten percentage points. At any given time the Fund may hold between 0% to 5% of its assets in real estate funds. The Fund’s composite benchmark is a composite of three benchmark indices representing three types of market sectors within the equity and fixed-income Underlying Fund asset classes, i.e., domestic equity, international equity and fixed-income. The composite index is created by applying the results of the benchmark for each of these three market sectors in proportion to the Fund’s target allocations among the three market sectors. For more information about the different indices that comprise the Fund’s composite benchmark index, please see “Additional Information About the Fund’s Composite Index” below.

The composition of the Fund’s fixed-income portion will vary depending on the shape of the yield curve. This means that when there is not much difference between the yield on short-term and long-term bonds, the Fund would normally increase its investments in the Short-Term Bond Fund. The Fund will have less than 5% of its assets in the High-Yield Fund.

The Fund might sometimes be even more heavily weighted toward equities or fixed-income, if the Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), believes market conditions warrant. For example, the Fund might increase its holdings in fixed-income funds in periods when Advisors believes equity markets will decline.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Board has authorized the Fund to invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”). The Fund may use investments in ETFs and ETNs to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

For flexibility in meeting redemptions, expenses and the timing of new investments, and as a short-term defense during periods of unusual volatility, the Fund may invest in government securities (as defined in the Investment Company Act of 1940, as amended (the “1940 Act”)), short-term paper or shares of the Money Market Fund. For temporary defensive purposes, the Managed Allocation Fund may invest without limitation in such securities. The Fund cannot guarantee that this strategy will be successful.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	60.16%	U.S. Equity	41.20%	ŸLarge-Cap Growth Fund	8.08%
				ŸEnhanced Large-Cap Growth Index Fund	7.79%
				ŸLarge-Cap Value Fund	7.53%
				ŸEnhanced Large-Cap Value Index Fund	7.28%
				ŸGrowth & Income Fund	6.70%
				ŸSmall-Cap Equity Fund	3.25%
				ŸMid-Cap Growth Fund	0.31%
				ŸMid-Cap Value Fund	0.26%
		International Equity	18.96%	ŸInternational Equity Fund	5.34%
				ŸEnhanced International Equity Index Fund	4.76%
				ŸInternational Opportunities Fund	4.48%
				ŸEmerging Markets Equity Fund	3.47%
				ŸGlobal Natural Resources Fund	0.91%
FIXED-INCOME	39.84%	Fixed-Income	39.83%	ŸBond Plus Fund	38.81%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. Accordingly, an investment in the Fund or the Underlying Funds typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The risks of investing in Underlying Funds with foreign investments include increased risks of adverse issuer, political, regulatory, currency, market or economic developments than investments in U.S. issuers, which can result in greater market and price volatility. These risks may be heightened in emerging or developing markets. Foreign investments may also be less liquid and more difficult to value than investments in U.S. issuers.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail and Retirement Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)†

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.18%.

Best quarter: 12.65%, for the quarter ended June 30, 2009. Worst quarter: -14.15%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Managed Allocation Fund		One Year	Five Years	Since Inception		Inception Date
Institutional Class		5.16%	9.92%	5.84%		Mar. 31, 2006
Retail Class		4.89%	9.66%	5.69%		Mar. 31, 2006
Retirement Class		4.91%	9.66%	5.57%		Mar. 31, 2006
After Taxes on Distributions | Institutional Class		3.29%	8.69%	4.66%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.63%	7.47%	4.22%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.75%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	5.19%	[1]
Managed Allocation Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.92%	9.54%	6.13%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retail Class shares; (ii) 0.25% of average daily net assets for Retirement Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Managed Allocation Fund Composite Index consisted of: 42.0% Russell 3000 Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifestyle Conservative Fund

TIAA-CREF Lifestyle Conservative Fund

Investment objective

The Fund seeks long-term total return, consisting of current income and capital appreciation.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifestyle Conservative Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifestyle Conservative Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees		0.25%		0.15%
Other Expenses		0.17%	0.40%	0.16%	0.15%
Acquired Fund Fees and Expenses	[1]	0.37%	0.37%	0.37%	0.37%
Total Annual Fund Operating Expenses		0.89%	0.87%	0.78%	0.62%
Waivers and Expense Reimbursements	[2]	(0.14%)	(0.15%)	(0.16%)	(0.15%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.75%	0.72%	0.62%	0.47%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifestyle Conservative Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 77	$ 74	$ 63	$ 48
3 Years	270	263	233	183
5 Years	479	468	418	331
10 Years	$ 1,083	$ 1,059	$ 951	$ 760

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term total return, consisting of current income and capital appreciation, through a relatively stable asset allocation strategy targeting a conservative risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 40% of the Fund’s assets in equity Underlying Funds and (2) approximately 60% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	40.15%	U.S. Equity	27.13%	ŸLarge-Cap Growth Fund	7.22%
				ŸLarge-Cap Value Fund	6.69%
				ŸGrowth & Income Fund	5.94%
				ŸEnhanced Large-Cap Growth Index Fund	2.41%
				ŸEnhanced Large-Cap Value Index Fund	2.22%
				ŸSmall-Cap Equity Fund	2.20%
				ŸMid-Cap Growth Fund	0.25%
				ŸMid-Cap Value Fund	0.20%
		International Equity	13.02%	ŸInternational Equity Fund	4.41%
				ŸInternational Opportunities Fund	2.97%
				ŸEnhanced International Equity Index Fund	2.54%
				ŸEmerging Markets Equity Fund	2.51%
				ŸGlobal Natural Resources Fund	0.59%
FIXED-INCOME	59.85%	Fixed-Income	39.92%	ŸBond Plus Fund	29.90%
				ŸBond Fund	9.00%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	19.93%	ŸShort-Term Bond Fund	19.93%
				ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Conservative Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.36%.

Best quarter: 6.70%, for the quarter ended March 31, 2012. Worst quarter: -1.24%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifestyle Conservative Fund		One Year	Since Inception		Inception Date
Institutional Class		4.28%	8.73%		Dec. 09, 2011
Retail Class		4.01%	8.41%		Dec. 09, 2011
Retirement Class		4.04%	8.45%		Dec. 09, 2011
Premier Class		4.14%	8.57%		Dec. 09, 2011
After Taxes on Distributions | Institutional Class		3.01%	7.60%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		2.72%	6.40%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	2.86%	[1]
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	20.13%	[1]
Lifestyle Conservative Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	5.56%	7.91%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Conservative Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 20.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 12.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle 2035 Fund

Risk/Return:

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Risk/Return [Heading]

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TIAA-CREF Lifecycle 2035 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Lifecycle 2035 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

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Sep. 30, 2016

Portfolio Turnover [Heading]

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Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

11.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2035.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 82.00% of the Fund’s assets to equity Underlying Funds and 18.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2035 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2042 to 2045. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 56.28%; International Equity: 24.12%; Fixed-Income: 19.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	82.27%	U.S. Equity	56.75%	ŸLarge-Cap Growth Fund	11.10%
				ŸEnhanced Large-Cap Growth Index Fund	10.76%
				ŸLarge-Cap Value Fund	10.28%
				ŸEnhanced Large-Cap Value Index Fund	10.01%
				ŸGrowth & Income Fund	9.12%
				ŸSmall-Cap Equity Fund	4.49%
				ŸMid-Cap Growth Fund	0.53%
				ŸMid-Cap Value Fund	0.46%
		International Equity	25.52%	ŸInternational Equity Fund	7.15%
				ŸEnhanced International Equity Index Fund	6.47%
				ŸInternational Opportunities Fund	6.13%
				ŸEmerging Markets Equity Fund	4.54%
				ŸGlobal Natural Resources Fund	1.23%
FIXED-INCOME	17.73%	Fixed-Income	17.72%	ŸBond Plus Fund	5.89%
				ŸBond Fund	5.88%
				ŸHigh-Yield Fund	4.97%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle 2035 Fund Composite Index consisted of: 58.0% Russell 3000® Index; 24.8% MSCI All Country World Index ex USA; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2035 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.84%.

Bar Chart Closing [Text Block]

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Best quarter: 17.55%, for the quarter ended June 30, 2009. Worst quarter: -20.30%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

3.84%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

17.55%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.30%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2035 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2035 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2035 Fund | Lifecycle 2035 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.22%

^[1]

Five Years

rr_AverageAnnualReturnYear05

11.51%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

6.21%

^[1]

TIAA-CREF Lifecycle 2035 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.85%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.68%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 69

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

254

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

455

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,033

Annual Return 2005

rr_AnnualReturn2005

5.16%

Annual Return 2006

rr_AnnualReturn2006

12.47%

Annual Return 2007

rr_AnnualReturn2007

9.71%

Annual Return 2008

rr_AnnualReturn2008

(38.18%)

Annual Return 2009

rr_AnnualReturn2009

28.30%

Annual Return 2010

rr_AnnualReturn2010

15.02%

Annual Return 2011

rr_AnnualReturn2011

(3.55%)

Annual Return 2012

rr_AnnualReturn2012

17.01%

Annual Return 2013

rr_AnnualReturn2013

24.40%

Annual Return 2014

rr_AnnualReturn2014

4.42%

One Year

rr_AverageAnnualReturnYear01

4.42%

Five Years

rr_AverageAnnualReturnYear05

11.01%

Ten Years

rr_AverageAnnualReturnYear10

5.67%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2035 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.67%

Five Years

rr_AverageAnnualReturnYear05

9.88%

Ten Years

rr_AverageAnnualReturnYear10

4.81%

TIAA-CREF Lifecycle 2035 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.46%

Five Years

rr_AverageAnnualReturnYear05

8.58%

Ten Years

rr_AverageAnnualReturnYear10

4.35%

TIAA-CREF Lifecycle 2035 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.70%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.58%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 59

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

212

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

378

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 859

One Year

rr_AverageAnnualReturnYear01

4.53%

Five Years

rr_AverageAnnualReturnYear05

11.12%

Ten Years

rr_AverageAnnualReturnYear10

5.73%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2035 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.55%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.43%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 44

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

164

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

295

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 678

One Year

rr_AverageAnnualReturnYear01

4.67%

Five Years

rr_AverageAnnualReturnYear05

11.28%

Ten Years

rr_AverageAnnualReturnYear10

5.88%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2035 Fund Composite Index consisted of: 58.0% Russell 3000 Index; 24.8% MSCI All Country World Index ex USA; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2010 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2010 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2010 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

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Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have recently retired or have an approximate target retirement year within a few years, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors who retired in 2010 or plan to retire within a few years of 2010. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 45.00% of the Fund’s assets to equity Underlying Funds and 55.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative. The Fund had target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2010 and will reach the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2017 to 2020. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 30.80%; International Equity: 13.20%; Fixed-Income: 39.20%; Short-Term Fixed-Income: 8.40%; and Inflation-Protected Assets: 8.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	45.11%	U.S. Equity	31.75%	ŸEquity Index Fund	31.75%
		International Equity	13.36%	ŸInternational Equity Index Fund	10.27%
				ŸEmerging Markets Equity Index Fund	3.09%
FIXED-INCOME	54.89%	Fixed-Income	46.94%	ŸBond Index Fund	46.94%
		Inflation-Protected Assets	7.95%	ŸInflation-Linked Bond Fund	7.95%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2010 Fund Composite Index consisted of: 46.7% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000® Index; 13.7% MSCI EAFE + Emerging Markets Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2010 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.25%.

Bar Chart Closing [Text Block]

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Best quarter: 7.77%, for the quarter ended September 30, 2010. Worst quarter: -6.63%, for the quarter ended September 30, 2011.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.25%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

7.77%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(6.63%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2010 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2010 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2010 Fund | Lifecycle Index 2010 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.47%

^[2]

Five Years

rr_AverageAnnualReturnYear05

8.47%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

8.60%

^[1],[2]

TIAA-CREF Lifecycle Index 2010 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.32%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.58%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

165

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

303

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 706

Annual Return 2010

rr_AnnualReturn2010

10.48%

Annual Return 2011

rr_AnnualReturn2011

3.07%

Annual Return 2012

rr_AnnualReturn2012

10.21%

Annual Return 2013

rr_AnnualReturn2013

10.55%

Annual Return 2014

rr_AnnualReturn2014

5.98%

One Year

rr_AverageAnnualReturnYear01

5.98%

Five Years

rr_AverageAnnualReturnYear05

8.01%

Since Inception

rr_AverageAnnualReturnSinceInception

8.13%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2010 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.20%

Five Years

rr_AverageAnnualReturnYear05

7.37%

Since Inception

rr_AverageAnnualReturnSinceInception

7.50%

TIAA-CREF Lifecycle Index 2010 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.57%

Five Years

rr_AverageAnnualReturnYear05

6.12%

Since Inception

rr_AverageAnnualReturnSinceInception

6.23%

TIAA-CREF Lifecycle Index 2010 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.43%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.16%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

122

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

225

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 527

One Year

rr_AverageAnnualReturnYear01

6.09%

Five Years

rr_AverageAnnualReturnYear05

8.14%

Since Inception

rr_AverageAnnualReturnSinceInception

8.25%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2010 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.28%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.16%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

74

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

141

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 340

One Year

rr_AverageAnnualReturnYear01

6.31%

Five Years

rr_AverageAnnualReturnYear05

8.30%

Since Inception

rr_AverageAnnualReturnSinceInception

8.42%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2010 Fund Composite Index consisted of: 46.7% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000 Index; 13.7% MSCI EAFE + Emerging Markets Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.09%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.26% of average daily net assets for Retirement Class shares; (ii) 0.16% of average daily net assets for Premier Class shares; and (iii) 0.01% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle 2030 Fund

TIAA-CREF Lifecycle 2030 Fund

Investment objective

The Lifecycle 2030 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2030 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2030 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.42%	0.42%	0.42%
Total Annual Fund Operating Expenses		0.84%	0.69%	0.54%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.67%	0.57%	0.42%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2030 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 68	$ 58	$ 43
3 Years	251	209	161
5 Years	449	372	290
10 Years	$ 1,021	$ 847	$ 666

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2030.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 74.00% of the Fund’s assets to equity Underlying Funds and 26.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2030 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2037 to 2040. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 50.68%; International Equity: 21.72%; Fixed-Income: 26.80%; Short-Term Fixed-Income: 0.40%; and Inflation-Protected Assets 0.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	74.28%	U.S. Equity	51.13%	ŸLarge-Cap Growth Fund	10.04%
				ŸEnhanced Large-Cap Growth Index Fund	9.70%
				ŸLarge-Cap Value Fund	9.27%
				ŸEnhanced Large-Cap Value Index Fund	9.02%
				ŸGrowth & Income Fund	8.25%
				ŸSmall-Cap Equity Fund	4.02%
				ŸMid-Cap Growth Fund	0.44%
				ŸMid-Cap Value Fund	0.39%
		International Equity	23.15%	ŸInternational Equity Fund	6.50%
				ŸEnhanced International Equity Index Fund	5.85%
				ŸInternational Opportunities Fund	5.54%
				ŸEmerging Markets Equity Fund	4.15%
				ŸGlobal Natural Resources Fund	1.11%
FIXED-INCOME	25.72%	Fixed-Income	25.71%	ŸBond Fund	9.98%
				ŸBond Plus Fund	9.78%
				ŸHigh-Yield Fund	4.97%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2030 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.53%.

Best quarter: 16.62%, for the quarter ended June 30, 2009. Worst quarter: -19.05%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2030 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.53%	10.52%	5.45%		Oct. 15, 2004
Institutional Class		4.71%	10.79%	5.65%	[1]	Jan. 17, 2007
Premier Class		4.68%	10.62%	5.50%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.79%	9.35%	4.57%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.47%	8.15%	4.15%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2030 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.12%	10.90%	5.95%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2030 Fund Composite Index consisted of: 52.4% Russell 3000 Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

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TIAA-CREF Lifecycle Index 2020 Fund

Risk/Return:

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Risk/Return [Heading]

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TIAA-CREF Lifecycle Index 2020 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Lifecycle Index 2020 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

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Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Portfolio Turnover, Rate

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9.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

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"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2020. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 58.00% of the Fund’s assets to equity Underlying Funds and 42.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2020 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2027 to 2030. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 39.48%; International Equity: 16.92%; Fixed-Income: 34.80%; Short-Term Fixed-Income: 4.40%; and Inflation-Protected Assets: 4.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	58.09%	U.S. Equity	40.90%	ŸEquity Index Fund	40.90%
		International Equity	17.19%	ŸInternational Equity Index Fund	13.21%
				ŸEmerging Markets Equity Index Fund	3.98%
FIXED-INCOME	41.91%	Fixed-Income	37.93%	ŸBond Index Fund	37.93%
		Inflation-Protected Assets	3.98%	ŸInflation-Linked Bond Fund	3.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle Index 2020 Fund Composite Index consisted of: 41.2% Russell 3000® Index; 37.4% Barclays U.S. Aggregate Bond Index; 17.6% MSCI EAFE + Emerging Markets Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2020 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.65%.

Bar Chart Closing [Text Block]

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Best quarter: 9.39%, for the quarter ended September 30, 2010. Worst quarter: -9.69%, for the quarter ended September 30, 2011.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.65%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

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9.39%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

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(9.69%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

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AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2020 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2020 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

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4.27%

^[1]

TIAA-CREF Lifecycle Index 2020 Fund | Lifecycle Index 2020 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

6.73%

^[2]

Five Years

rr_AverageAnnualReturnYear05

9.63%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

9.86%

^[1],[2]

TIAA-CREF Lifecycle Index 2020 Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

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none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

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none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.52%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

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152

Expense Example, with Redemption, 5 Years

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276

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 638

Annual Return 2010

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11.69%

Annual Return 2011

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1.32%

Annual Return 2012

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11.96%

Annual Return 2013

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15.27%

Annual Return 2014

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6.27%

One Year

rr_AverageAnnualReturnYear01

6.27%

Five Years

rr_AverageAnnualReturnYear05

9.19%

Since Inception

rr_AverageAnnualReturnSinceInception

9.39%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2020 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.57%

Five Years

rr_AverageAnnualReturnYear05

8.65%

Since Inception

rr_AverageAnnualReturnSinceInception

8.86%

TIAA-CREF Lifecycle Index 2020 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.77%

Five Years

rr_AverageAnnualReturnYear05

7.15%

Since Inception

rr_AverageAnnualReturnSinceInception

7.33%

TIAA-CREF Lifecycle Index 2020 Fund | Premier Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.37%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

109

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

198

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 458

One Year

rr_AverageAnnualReturnYear01

6.36%

Five Years

rr_AverageAnnualReturnYear05

9.28%

Since Inception

rr_AverageAnnualReturnSinceInception

9.48%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2020 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.09%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.22%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

61

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

114

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 270

One Year

rr_AverageAnnualReturnYear01

6.48%

Five Years

rr_AverageAnnualReturnYear05

9.46%

Since Inception

rr_AverageAnnualReturnSinceInception

9.65%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2020 Fund Composite Index consisted of: 41.2% Russell 3000 Index; 37.4% Barclays U.S. Aggregate Bond Index; 17.6% MSCI EAFE + Emerging Markets Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.07%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.28% of average daily net assets for Retirement Class shares; (ii) 0.18% of average daily net assets for Premier Class shares; and (iii) 0.03% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Managed Allocation Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Managed Allocation Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Fund seeks favorable returns that reflect the broad investment performance of the financial markets through capital appreciation and investment income. The Fund will pursue this goal through a “fund of funds” approach, whereby the Fund will make investments primarily in other mutual funds.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

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"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy and will generally seek to meet its investment objective by investing: (1) approximately 60.00% of its assets in equity Underlying Funds including up to 5% of its assets in real estate Underlying Funds; and (2) approximately 40.00% of its assets in fixed-income Underlying Funds (“target allocations”).

The Fund currently intends to invest in the following equity Underlying Funds: Growth & Income Fund, International Equity Fund, International Opportunities Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Emerging Markets Equity Fund, Small-Cap Equity Fund, Enhanced International Equity Index Fund, Enhanced Large-Cap Growth Index Fund, Enhanced Large-Cap Value Index Fund, Global Natural Resources Fund and Real Estate Securities Fund.

The Fund currently intends to invest in the following fixed-income Underlying Funds: Bond Plus Fund, Short-Term Bond Fund, High-Yield Fund and Inflation-Linked Bond Fund.

As a result of its investments in the Underlying Funds, the Managed Allocation Fund’s returns will reflect investments in a mix of domestic stocks of companies of all sizes, foreign equities, real estate securities and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the foreign and domestic equity markets, as well as overall financial and economic conditions. If the portfolio managers believe that the relative attractiveness of the markets in which the equity and fixed-income funds are invested changes, they can adjust the percentage of investments in these Underlying Funds up or down by up to ten percentage points. At any given time the Fund may hold between 0% to 5% of its assets in real estate funds. The Fund’s composite benchmark is a composite of three benchmark indices representing three types of market sectors within the equity and fixed-income Underlying Fund asset classes, i.e., domestic equity, international equity and fixed-income. The composite index is created by applying the results of the benchmark for each of these three market sectors in proportion to the Fund’s target allocations among the three market sectors. For more information about the different indices that comprise the Fund’s composite benchmark index, please see “Additional Information About the Fund’s Composite Index” below.

The composition of the Fund’s fixed-income portion will vary depending on the shape of the yield curve. This means that when there is not much difference between the yield on short-term and long-term bonds, the Fund would normally increase its investments in the Short-Term Bond Fund. The Fund will have less than 5% of its assets in the High-Yield Fund.

The Fund might sometimes be even more heavily weighted toward equities or fixed-income, if the Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), believes market conditions warrant. For example, the Fund might increase its holdings in fixed-income funds in periods when Advisors believes equity markets will decline.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Board has authorized the Fund to invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”). The Fund may use investments in ETFs and ETNs to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

For flexibility in meeting redemptions, expenses and the timing of new investments, and as a short-term defense during periods of unusual volatility, the Fund may invest in government securities (as defined in the Investment Company Act of 1940, as amended (the “1940 Act”)), short-term paper or shares of the Money Market Fund. For temporary defensive purposes, the Managed Allocation Fund may invest without limitation in such securities. The Fund cannot guarantee that this strategy will be successful.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	60.16%	U.S. Equity	41.20%	ŸLarge-Cap Growth Fund	8.08%
				ŸEnhanced Large-Cap Growth Index Fund	7.79%
				ŸLarge-Cap Value Fund	7.53%
				ŸEnhanced Large-Cap Value Index Fund	7.28%
				ŸGrowth & Income Fund	6.70%
				ŸSmall-Cap Equity Fund	3.25%
				ŸMid-Cap Growth Fund	0.31%
				ŸMid-Cap Value Fund	0.26%
		International Equity	18.96%	ŸInternational Equity Fund	5.34%
				ŸEnhanced International Equity Index Fund	4.76%
				ŸInternational Opportunities Fund	4.48%
				ŸEmerging Markets Equity Fund	3.47%
				ŸGlobal Natural Resources Fund	0.91%
FIXED-INCOME	39.84%	Fixed-Income	39.83%	ŸBond Plus Fund	38.81%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. Accordingly, an investment in the Fund or the Underlying Funds typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The risks of investing in Underlying Funds with foreign investments include increased risks of adverse issuer, political, regulatory, currency, market or economic developments than investments in U.S. issuers, which can result in greater market and price volatility. These risks may be heightened in emerging or developing markets. Foreign investments may also be less liquid and more difficult to value than investments in U.S. issuers.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail and Retirement Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Managed Allocation Fund Composite Index consisted of: 42.0% Russell 3000® Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)†

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.18%.

Bar Chart Closing [Text Block]

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Best quarter: 12.65%, for the quarter ended June 30, 2009. Worst quarter: -14.15%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

3.18%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

12.65%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.15%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Managed Allocation Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

7.75%

^[1]

TIAA-CREF Managed Allocation Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

5.19%

^[1]

TIAA-CREF Managed Allocation Fund | Managed Allocation Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.92%

^[2]

Five Years

rr_AverageAnnualReturnYear05

9.54%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

6.13%

^[1],[2]

TIAA-CREF Managed Allocation Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.72%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.07%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.65%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 66

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

223

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

394

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 888

One Year

rr_AverageAnnualReturnYear01

4.89%

Five Years

rr_AverageAnnualReturnYear05

9.66%

Since Inception

rr_AverageAnnualReturnSinceInception

5.69%

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2006

TIAA-CREF Managed Allocation Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.68%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.03%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.65%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 66

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

215

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

376

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 844

One Year

rr_AverageAnnualReturnYear01

4.91%

Five Years

rr_AverageAnnualReturnYear05

9.66%

Since Inception

rr_AverageAnnualReturnSinceInception

5.57%

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2006

TIAA-CREF Managed Allocation Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.43%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.03%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.40%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 41

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

135

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

238

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 539

Annual Return 2007

rr_AnnualReturn2007

8.83%

Annual Return 2008

rr_AnnualReturn2008

(28.64%)

Annual Return 2009

rr_AnnualReturn2009

22.46%

Annual Return 2010

rr_AnnualReturn2010

13.44%

Annual Return 2011

rr_AnnualReturn2011

0.31%

Annual Return 2012

rr_AnnualReturn2012

14.65%

Annual Return 2013

rr_AnnualReturn2013

16.96%

Annual Return 2014

rr_AnnualReturn2014

5.16%

One Year

rr_AverageAnnualReturnYear01

5.16%

Five Years

rr_AverageAnnualReturnYear05

9.92%

Since Inception

rr_AverageAnnualReturnSinceInception

5.84%

Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 31, 2006

TIAA-CREF Managed Allocation Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.29%

Five Years

rr_AverageAnnualReturnYear05

8.69%

Since Inception

rr_AverageAnnualReturnSinceInception

4.66%

TIAA-CREF Managed Allocation Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.63%

Five Years

rr_AverageAnnualReturnYear05

7.47%

Since Inception

rr_AverageAnnualReturnSinceInception

4.22%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Managed Allocation Fund Composite Index consisted of: 42.0% Russell 3000 Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retail Class shares; (ii) 0.25% of average daily net assets for Retirement Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle 2010 Fund

TIAA-CREF Lifecycle 2010 Fund

Investment objective

The Lifecycle 2010 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2010 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2010 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.37%	0.37%	0.37%
Total Annual Fund Operating Expenses		0.79%	0.64%	0.49%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.62%	0.52%	0.37%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2010 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 63	$ 53	$ 38
3 Years	235	193	145
5 Years	422	345	262
10 Years	$ 962	$ 787	$ 604

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 20% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have recently retired or have an approximate target retirement year within a few years, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors who retired in 2010 or plan to retire within a few years of 2010.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 45.00% of the Fund’s assets to equity Underlying Funds and 55.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative. The Fund had target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2010 and will reach the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2017 to 2020. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 30.80%; International Equity: 13.20%; Fixed-Income: 39.20%; Short-Term Fixed-Income: 8.40%; and Inflation-Protected Assets: 8.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	45.35%	U.S. Equity	30.76%	ŸLarge-Cap Growth Fund	6.15%
				ŸEnhanced Large-Cap Growth Index Fund	5.81%
				ŸLarge-Cap Value Fund	5.62%
				ŸEnhanced Large-Cap Value Index Fund	5.41%
				ŸGrowth & Income Fund	5.05%
				ŸSmall-Cap Equity Fund	2.44%
				ŸMid-Cap Growth Fund	0.16%
				ŸMid-Cap Value Fund	0.12%
		International Equity	14.59%	ŸInternational Equity Fund	4.17%
				ŸEnhanced International Equity Index Fund	3.60%
				ŸInternational Opportunities Fund	3.37%
				ŸEmerging Markets Equity Fund	2.77%
				ŸGlobal Natural Resources Fund	0.68%
FIXED-INCOME	54.65%	Fixed-Income	38.72%	ŸBond Fund	23.84%
				ŸBond Plus Fund	10.91%
				ŸHigh-Yield Fund	2.98%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	7.92%	ŸShort-Term Bond Fund	7.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	8.01%	ŸInflation-Linked Bond Fund	8.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2010 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.26%.

Best quarter: 10.87%, for the quarter ended June 30, 2009. Worst quarter: -11.04%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2010 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.38%	8.19%	5.25%		Oct. 15, 2004
Institutional Class		4.59%	8.46%	5.46%	[1]	Jan. 17, 2007
Premier Class		4.44%	8.30%	5.30%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.91%	7.15%	4.34%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		2.94%	6.12%	3.87%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Lifecycle 2010 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.13%	8.31%	5.57%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2010 Fund Composite Index consisted of: 38.9% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000 Index; 13.7% MSCI All Country World Index ex USA; 7.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2040 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2040 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2040 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

6.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2040. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2040 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2047 to 2050. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 61.88%; International Equity: 26.52%; Fixed-Income: 11.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.98%	U.S. Equity	63.30%	ŸEquity Index Fund	63.30%
		International Equity	26.68%	ŸInternational Equity Index Fund	20.50%
				ŸEmerging Markets Equity Index Fund	6.18%
FIXED-INCOME	10.02%	Fixed-Income	10.02%	ŸBond Index Fund	10.02%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2040 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2040 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.59%.

Bar Chart Closing [Text Block]

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Best quarter: 11.87%, for the quarter ended September 30, 2010. Worst quarter: -14.82%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.59%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.87%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.82%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2040 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2040 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2040 Fund | Lifecycle Index 2040 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.18%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.84%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

12.17%

^[1],[2]

TIAA-CREF Lifecycle Index 2040 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.50%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

147

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

267

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 616

Annual Return 2010

rr_AnnualReturn2010

13.50%

Annual Return 2011

rr_AnnualReturn2011

(1.70%)

Annual Return 2012

rr_AnnualReturn2012

15.46%

Annual Return 2013

rr_AnnualReturn2013

24.87%

Annual Return 2014

rr_AnnualReturn2014

6.56%

One Year

rr_AverageAnnualReturnYear01

6.56%

Five Years

rr_AverageAnnualReturnYear05

11.38%

Since Inception

rr_AverageAnnualReturnSinceInception

11.70%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2040 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.92%

Five Years

rr_AverageAnnualReturnYear05

10.90%

Since Inception

rr_AverageAnnualReturnSinceInception

11.23%

TIAA-CREF Lifecycle Index 2040 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.05%

Five Years

rr_AverageAnnualReturnYear05

9.02%

Since Inception

rr_AverageAnnualReturnSinceInception

9.31%

TIAA-CREF Lifecycle Index 2040 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.35%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.08%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

104

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

188

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 435

One Year

rr_AverageAnnualReturnYear01

6.65%

Five Years

rr_AverageAnnualReturnYear05

11.47%

Since Inception

rr_AverageAnnualReturnSinceInception

11.79%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2040 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.20%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.08%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

56

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

105

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 247

One Year

rr_AverageAnnualReturnYear01

6.85%

Five Years

rr_AverageAnnualReturnYear05

11.65%

Since Inception

rr_AverageAnnualReturnSinceInception

11.97%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2040 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifestyle Income Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifestyle Income Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks current income with some capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

13.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking current income with some capital appreciation through a relatively stable asset allocation strategy targeting an income-oriented and conservative risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 20% of the Fund’s assets in equity Underlying Funds and (2) approximately 80% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	20.15%	U.S. Equity	13.62%	ŸLarge-Cap Growth Fund	3.63%
				ŸLarge-Cap Value Fund	3.36%
				ŸGrowth & Income Fund	2.98%
				ŸEnhanced Large-Cap Growth Index Fund	1.21%
				ŸEnhanced Large-Cap Value Index Fund	1.11%
				ŸSmall-Cap Equity Fund	1.10%
				ŸMid-Cap Growth Fund	0.13%
				ŸMid-Cap Value Fund	0.10%
		International Equity	6.53%	ŸInternational Equity Fund	2.20%
				ŸInternational Opportunities Fund	1.49%
				ŸEnhanced International Equity Index Fund	1.28%
				ŸEmerging Markets Equity Fund	1.26%
				ŸGlobal Natural Resources Fund	0.30%
FIXED-INCOME	79.85%	Fixed-Income	39.89%	ŸBond Plus Fund	19.88%
				ŸBond Fund	18.99%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	39.96%	ŸShort-Term Bond Fund	39.96%
				ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a higher percentage of fixed-income Underlying Funds, Fixed-Income Underlying Fund Risks are expected to predominate.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income;

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available; and

· Fixed-income foreign investment risk—Investment in fixed-income securities or financial instruments of foreign issuers involves increased risks due to adverse issuer, political, regulatory, currency, market or economic developments. These developments may impact the ability of a foreign debt issuer to make timely and ultimate payments on its debt obligations to the Fund or impair the Fund’s ability to enforce its rights against the foreign debt issuer. These risks are heightened in emerging or developing markets.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets; and

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifestyle Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 40.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; 14.0% Russell 3000® Index; and 6.0% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Income Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.43%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 3.94%, for the quarter ended March 31, 2012. Worst quarter: -1.39%, for the quarter ended June 30, 2013.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.43%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

3.94%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2013

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(1.39%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifestyle Income Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

2.86%

^[1]

TIAA-CREF Lifestyle Income Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

20.13%

^[1]

TIAA-CREF Lifestyle Income Fund | Lifestyle Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.20%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

4.83%

^[1],[2]

TIAA-CREF Lifestyle Income Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.33%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.95%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.24%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.71%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 73

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

279

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

502

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,144

One Year

rr_AverageAnnualReturnYear01

3.18%

Since Inception

rr_AverageAnnualReturnSinceInception

5.34%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Income Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.49%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.33%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.92%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.24%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.68%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 69

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

269

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

486

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,109

One Year

rr_AverageAnnualReturnYear01

3.30%

Since Inception

rr_AverageAnnualReturnSinceInception

5.38%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Income Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

Other Expenses

rr_OtherExpensesOverAssets

0.25%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.33%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.83%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.25%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.58%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 59

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

240

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

436

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,002

One Year

rr_AverageAnnualReturnYear01

3.40%

Since Inception

rr_AverageAnnualReturnSinceInception

5.49%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Income Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.25%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.33%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.68%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.25%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.43%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 44

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

192

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

354

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 823

Annual Return 2012

rr_AnnualReturn2012

8.53%

Annual Return 2013

rr_AnnualReturn2013

5.05%

Annual Return 2014

rr_AnnualReturn2014

3.54%

One Year

rr_AverageAnnualReturnYear01

3.54%

Since Inception

rr_AverageAnnualReturnSinceInception

5.64%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Income Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.44%

Since Inception

rr_AverageAnnualReturnSinceInception

4.57%

TIAA-CREF Lifestyle Income Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.20%

Since Inception

rr_AverageAnnualReturnSinceInception

3.98%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 40.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; 14.0% Russell 3000 Index; and 6.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2030 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2030 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2030 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

11.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2030.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 74.00% of the Fund’s assets to equity Underlying Funds and 26.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2030 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2037 to 2040. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 50.68%; International Equity: 21.72%; Fixed-Income: 26.80%; Short-Term Fixed-Income: 0.40%; and Inflation-Protected Assets 0.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	74.28%	U.S. Equity	51.13%	ŸLarge-Cap Growth Fund	10.04%
				ŸEnhanced Large-Cap Growth Index Fund	9.70%
				ŸLarge-Cap Value Fund	9.27%
				ŸEnhanced Large-Cap Value Index Fund	9.02%
				ŸGrowth & Income Fund	8.25%
				ŸSmall-Cap Equity Fund	4.02%
				ŸMid-Cap Growth Fund	0.44%
				ŸMid-Cap Value Fund	0.39%
		International Equity	23.15%	ŸInternational Equity Fund	6.50%
				ŸEnhanced International Equity Index Fund	5.85%
				ŸInternational Opportunities Fund	5.54%
				ŸEmerging Markets Equity Fund	4.15%
				ŸGlobal Natural Resources Fund	1.11%
FIXED-INCOME	25.72%	Fixed-Income	25.71%	ŸBond Fund	9.98%
				ŸBond Plus Fund	9.78%
				ŸHigh-Yield Fund	4.97%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle 2030 Fund Composite Index consisted of: 52.4% Russell 3000® Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2030 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.53%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 16.62%, for the quarter ended June 30, 2009. Worst quarter: -19.05%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

3.53%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

16.62%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(19.05%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2030 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2030 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2030 Fund | Lifecycle 2030 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.12%

^[1]

Five Years

rr_AverageAnnualReturnYear05

10.90%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

5.95%

^[1]

TIAA-CREF Lifecycle 2030 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.42%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.84%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.67%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 68

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

251

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

449

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,021

Annual Return 2005

rr_AnnualReturn2005

4.90%

Annual Return 2006

rr_AnnualReturn2006

11.72%

Annual Return 2007

rr_AnnualReturn2007

9.39%

Annual Return 2008

rr_AnnualReturn2008

(36.54%)

Annual Return 2009

rr_AnnualReturn2009

26.70%

Annual Return 2010

rr_AnnualReturn2010

14.39%

Annual Return 2011

rr_AnnualReturn2011

(2.61%)

Annual Return 2012

rr_AnnualReturn2012

16.21%

Annual Return 2013

rr_AnnualReturn2013

21.84%

Annual Return 2014

rr_AnnualReturn2014

4.53%

One Year

rr_AverageAnnualReturnYear01

4.53%

Five Years

rr_AverageAnnualReturnYear05

10.52%

Ten Years

rr_AverageAnnualReturnYear10

5.45%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2030 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.79%

Five Years

rr_AverageAnnualReturnYear05

9.35%

Ten Years

rr_AverageAnnualReturnYear10

4.57%

TIAA-CREF Lifecycle 2030 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.47%

Five Years

rr_AverageAnnualReturnYear05

8.15%

Ten Years

rr_AverageAnnualReturnYear10

4.15%

TIAA-CREF Lifecycle 2030 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.42%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.69%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.57%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 58

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

209

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

372

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 847

One Year

rr_AverageAnnualReturnYear01

4.68%

Five Years

rr_AverageAnnualReturnYear05

10.62%

Ten Years

rr_AverageAnnualReturnYear10

5.50%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2030 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.42%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.54%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.42%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 43

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

161

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

290

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 666

One Year

rr_AverageAnnualReturnYear01

4.71%

Five Years

rr_AverageAnnualReturnYear05

10.79%

Ten Years

rr_AverageAnnualReturnYear10

5.65%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2030 Fund Composite Index consisted of: 52.4% Russell 3000 Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2020 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2020 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2020 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

13.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2020.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 58.00% of the Fund’s assets to equity Underlying Funds and 42.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2020 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2027 to 2030. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 39.48%; International Equity: 16.92%; Fixed-Income: 34.81%; Short-Term Fixed-Income: 4.40%; and Inflation-Protected Assets: 4.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund, and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	58.33%	U.S. Equity	39.86%	ŸLarge-Cap Growth Fund	7.83%
				ŸEnhanced Large-Cap Growth Index Fund	7.55%
				ŸLarge-Cap Value Fund	7.27%
				ŸEnhanced Large-Cap Value Index Fund	7.04%
				ŸGrowth & Income Fund	6.49%
				ŸSmall-Cap Equity Fund	3.15%
				ŸMid-Cap Growth Fund	0.29%
				ŸMid-Cap Value Fund	0.24%
		International Equity	18.47%	ŸInternational Equity Fund	5.22%
				ŸEnhanced International Equity Index Fund	4.60%
				ŸInternational Opportunities Fund	4.37%
				ŸEmerging Markets Equity Fund	3.38%
				ŸGlobal Natural Resources Fund	0.90%
FIXED-INCOME	41.67%	Fixed-Income	33.76%	ŸBond Fund	18.88%
				ŸBond Plus Fund	10.89%
				ŸHigh-Yield Fund	3.00%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	3.92%	ŸShort-Term Bond Fund	3.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	3.99%	ŸInflation-Linked Bond Fund	3.99%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle 2020 Fund Composite Index consisted of: 41.2% Russell 3000® Index; 33.6% Barclays U.S. Aggregate Bond Index; 17.6% MSCI All Country World Index ex USA; 3.8% Barclays U.S. 1–3 Year Government/Credit Bond Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2020 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.90%.

Bar Chart Closing [Text Block]

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Best quarter: 13.85%, for the quarter ended June 30, 2009. Worst quarter: -14.95%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.90%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

13.85%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.95%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2020 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2020 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2020 Fund | Lifecycle 2020 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.63%

^[1]

Five Years

rr_AverageAnnualReturnYear05

9.57%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

5.79%

^[1]

TIAA-CREF Lifecycle 2020 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.39%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.81%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.64%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 65

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

242

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

433

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 986

Annual Return 2005

rr_AnnualReturn2005

4.77%

Annual Return 2006

rr_AnnualReturn2006

10.26%

Annual Return 2007

rr_AnnualReturn2007

9.22%

Annual Return 2008

rr_AnnualReturn2008

(30.33%)

Annual Return 2009

rr_AnnualReturn2009

23.15%

Annual Return 2010

rr_AnnualReturn2010

13.15%

Annual Return 2011

rr_AnnualReturn2011

(0.52%)

Annual Return 2012

rr_AnnualReturn2012

14.28%

Annual Return 2013

rr_AnnualReturn2013

16.30%

Annual Return 2014

rr_AnnualReturn2014

4.52%

One Year

rr_AverageAnnualReturnYear01

4.52%

Five Years

rr_AverageAnnualReturnYear05

9.35%

Ten Years

rr_AverageAnnualReturnYear10

5.41%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2020 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.76%

Five Years

rr_AverageAnnualReturnYear05

8.11%

Ten Years

rr_AverageAnnualReturnYear10

4.45%

TIAA-CREF Lifecycle 2020 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.42%

Five Years

rr_AverageAnnualReturnYear05

7.15%

Ten Years

rr_AverageAnnualReturnYear10

4.07%

TIAA-CREF Lifecycle 2020 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.39%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.66%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.54%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 55

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

199

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

356

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 811

One Year

rr_AverageAnnualReturnYear01

4.62%

Five Years

rr_AverageAnnualReturnYear05

9.46%

Ten Years

rr_AverageAnnualReturnYear10

5.46%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2020 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.39%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.51%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.39%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 40

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

151

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

273

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 629

One Year

rr_AverageAnnualReturnYear01

4.86%

Five Years

rr_AverageAnnualReturnYear05

9.64%

Ten Years

rr_AverageAnnualReturnYear10

5.61%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2020 Fund Composite Index consisted of: 41.2% Russell 3000 Index; 33.6% Barclays U.S. Aggregate Bond Index; 17.6% MSCI All Country World Index ex USA; 3.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

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TIAA-CREF Lifecycle 2035 Fund

TIAA-CREF Lifecycle 2035 Fund

Investment objective

The Lifecycle 2035 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2035 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2035 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.43%	0.43%	0.43%
Total Annual Fund Operating Expenses		0.85%	0.70%	0.55%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.68%	0.58%	0.43%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2035 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 69	$ 59	$ 44
3 Years	254	212	164
5 Years	455	378	295
10 Years	$ 1,033	$ 859	$ 678

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2035.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 82.00% of the Fund’s assets to equity Underlying Funds and 18.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2035 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2042 to 2045. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 56.28%; International Equity: 24.12%; Fixed-Income: 19.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	82.27%	U.S. Equity	56.75%	ŸLarge-Cap Growth Fund	11.10%
				ŸEnhanced Large-Cap Growth Index Fund	10.76%
				ŸLarge-Cap Value Fund	10.28%
				ŸEnhanced Large-Cap Value Index Fund	10.01%
				ŸGrowth & Income Fund	9.12%
				ŸSmall-Cap Equity Fund	4.49%
				ŸMid-Cap Growth Fund	0.53%
				ŸMid-Cap Value Fund	0.46%
		International Equity	25.52%	ŸInternational Equity Fund	7.15%
				ŸEnhanced International Equity Index Fund	6.47%
				ŸInternational Opportunities Fund	6.13%
				ŸEmerging Markets Equity Fund	4.54%
				ŸGlobal Natural Resources Fund	1.23%
FIXED-INCOME	17.73%	Fixed-Income	17.72%	ŸBond Plus Fund	5.89%
				ŸBond Fund	5.88%
				ŸHigh-Yield Fund	4.97%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2035 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.84%.

Best quarter: 17.55%, for the quarter ended June 30, 2009. Worst quarter: -20.30%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2035 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.42%	11.01%	5.67%		Oct. 15, 2004
Institutional Class		4.67%	11.28%	5.88%	[1]	Jan. 17, 2007
Premier Class		4.53%	11.12%	5.73%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.67%	9.88%	4.81%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.46%	8.58%	4.35%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2035 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.22%	11.51%	6.21%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2035 Fund Composite Index consisted of: 58.0% Russell 3000 Index; 24.8% MSCI All Country World Index ex USA; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle 2025 Fund

TIAA-CREF Lifecycle 2025 Fund

Investment objective

The Lifecycle 2025 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2025 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2025 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.41%	0.41%	0.41%
Total Annual Fund Operating Expenses		0.83%	0.68%	0.53%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.66%	0.56%	0.41%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2025 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 67	$ 57	$ 42
3 Years	248	205	158
5 Years	444	367	284
10 Years	$ 1,010	$ 835	$ 653

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2025.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 66.00% of the Fund’s assets to equity Underlying Funds and 34.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2025 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2032 to 2035. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 45.08%; International Equity: 19.32%; Fixed-Income: 30.80%; Short-Term Fixed-Income: 2.4%; and Inflation-Protected Assets: 2.4%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	66.30%	U.S. Equity	45.50%	ŸLarge-Cap Growth Fund	8.92%
				ŸEnhanced Large-Cap Growth Index Fund	8.62%
				ŸLarge-Cap Value Fund	8.29%
				ŸEnhanced Large-Cap Value Index Fund	8.03%
				ŸGrowth & Income Fund	7.37%
				ŸSmall-Cap Equity Fund	3.58%
				ŸMid-Cap Growth Fund	0.37%
				ŸMid-Cap Value Fund	0.32%
		International Equity	20.80%	ŸInternational Equity Fund	5.86%
				ŸEnhanced International Equity Index Fund	5.23%
				ŸInternational Opportunities Fund	4.95%
				ŸEmerging Markets Equity Fund	3.75%
				ŸGlobal Natural Resources Fund	1.01%
FIXED-INCOME	33.70%	Fixed-Income	29.79%	ŸBond Fund	13.98%
				ŸBond Plus Fund	10.83%
				ŸHigh-Yield Fund	3.99%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	1.93%	ŸShort-Term Bond Fund	1.92%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	1.98%	ŸInflation-Linked Bond Fund	1.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2025 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.18%.

Best quarter: 15.33%, for the quarter ended June 30, 2009. Worst quarter: -16.97%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2025 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.56%	9.98%	5.46%		Oct. 15, 2004
Institutional Class		4.87%	10.23%	5.67%	[1]	Jan. 17, 2007
Premier Class		4.73%	10.06%	5.51%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.81%	8.76%	4.54%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.46%	7.68%	4.14%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2025 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.89%	10.25%	5.88%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2025 Fund Composite Index consisted of: 46.8% Russell 3000 Index; 29.6% Barclays U.S. Aggregate Bond Index; 20.0% MSCI All Country World Index ex USA; 1.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle Retirement Income Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Retirement Income Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Retirement Income Fund seeks high total return over time primarily through income,

Objective, Secondary [Text Block]

rr_ObjectiveSecondaryTextBlock

with a secondary emphasis on capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 19% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

19.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016 but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy that will not gradually adjust over time and is designed for investors who are already in or entering retirement (i.e., have already passed their retirement year).

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 40.00% of the Fund’s assets to equity Underlying Funds and 60.00% of its assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations may be changed and actual allocations may vary up to ten percentage points from the targets. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which may change, are approximately as follows: U.S. Equity: 28%; International Equity: 12%; Fixed-Income: 40%; Short-Term Fixed-Income: 10%; and Inflation-Protected Assets: 10%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change. Investors should note that the Fund has a significant level of equity exposure and this exposure could cause fluctuation in the value of the Fund depending on the performance of the equity markets generally.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	40.26%	U.S. Equity	27.19%	ŸLarge-Cap Growth Fund	5.44%
				ŸEnhanced Large-Cap Growth Index Fund	5.12%
				ŸLarge-Cap Value Fund	5.04%
				ŸEnhanced Large-Cap Value Index Fund	4.75%
				ŸGrowth & Income Fund	4.47%
				ŸSmall-Cap Equity Fund	2.18%
				ŸMid-Cap Growth Fund	0.11%
				ŸMid-Cap Value Fund	0.08%
		International Equity	13.07%	ŸInternational Equity Fund	3.78%
				ŸEnhanced International Equity Index Fund	3.18%
				ŸInternational Opportunities Fund	3.00%
				ŸEmerging Markets Equity Fund	2.51%
				ŸGlobal Natural Resources Fund	0.60%
FIXED-INCOME	59.74%	Fixed-Income	39.78%	ŸBond Fund	24.85%
				ŸBond Plus Fund	10.95%
				ŸHigh-Yield Fund	2.99%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	10.01%	ŸShort-Term Bond Fund	10.00%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	9.95%	ŸInflation-Linked Bond Fund	9.95%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional, Retail and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Retirement Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000® Index; 12.0% MSCI All Country World Index ex USA; 10.0% Barclays U.S. 1–3 Year Government/Credit Bond Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Retirement Income Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.07%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 8.88%, for the quarter ended September 30, 2009. Worst quarter: -7.81%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.07%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

8.88%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(7.81%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Retirement Income Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.76%

^[1]

TIAA-CREF Lifecycle Retirement Income Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

7.35%

^[1]

TIAA-CREF Lifecycle Retirement Income Fund | Lifecycle Retirement Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.86%

^[2]

Five Years

rr_AverageAnnualReturnYear05

7.63%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

5.09%

^[1],[2]

TIAA-CREF Lifecycle Retirement Income Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.08%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.79%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.61%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 62

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

234

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

421

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 961

One Year

rr_AverageAnnualReturnYear01

4.18%

Five Years

rr_AverageAnnualReturnYear05

7.56%

Since Inception

rr_AverageAnnualReturnSinceInception

4.71%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

TIAA-CREF Lifecycle Retirement Income Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.30%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.81%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.61%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 62

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

239

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

430

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 983

One Year

rr_AverageAnnualReturnYear01

4.18%

Five Years

rr_AverageAnnualReturnYear05

7.54%

Since Inception

rr_AverageAnnualReturnSinceInception

4.63%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

TIAA-CREF Lifecycle Retirement Income Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.82%

Five Years

rr_AverageAnnualReturnYear05

6.49%

Since Inception

rr_AverageAnnualReturnSinceInception

3.58%

TIAA-CREF Lifecycle Retirement Income Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.71%

Five Years

rr_AverageAnnualReturnYear05

5.58%

Since Inception

rr_AverageAnnualReturnSinceInception

3.25%

TIAA-CREF Lifecycle Retirement Income Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.05%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.66%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.51%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 52

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

196

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

353

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 808

One Year

rr_AverageAnnualReturnYear01

4.38%

Five Years

rr_AverageAnnualReturnYear05

7.66%

Since Inception

rr_AverageAnnualReturnSinceInception

4.71%

^[7]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Retirement Income Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.05%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.51%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.36%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 37

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

148

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

270

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 626

Annual Return 2008

rr_AnnualReturn2008

(17.49%)

Annual Return 2009

rr_AnnualReturn2009

16.08%

Annual Return 2010

rr_AnnualReturn2010

10.44%

Annual Return 2011

rr_AnnualReturn2011

2.41%

Annual Return 2012

rr_AnnualReturn2012

11.27%

Annual Return 2013

rr_AnnualReturn2013

9.70%

Annual Return 2014

rr_AnnualReturn2014

4.18%

One Year

rr_AverageAnnualReturnYear01

4.53%

Five Years

rr_AverageAnnualReturnYear05

7.81%

Since Inception

rr_AverageAnnualReturnSinceInception

4.89%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Retirement Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 12.0% MSCI All Country World Index ex USA; 10.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retail Class shares; (ii) 0.25% of average daily net assets for Retirement Class shares; (iii) 0.15% of average daily net assets for Premier Class shares; and (iv) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[7] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2060 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2060 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2060 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal period between September 26, 2014 (inception date) and May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

12.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2060.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2060 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2067 to 2070. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s target asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, for June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.13%	U.S. Equity	62.29%	ŸLarge-Cap Growth Fund	12.19%
				ŸEnhanced Large-Cap Growth Index Fund	11.82%
				ŸLarge-Cap Value Fund	11.25%
				ŸEnhanced Large-Cap Value Index Fund	11.01%
				ŸGrowth & Income Fund	9.98%
				ŸSmall-Cap Equity Fund	4.88%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.54%
		International Equity	27.84%	ŸInternational Equity Fund	7.79%
				ŸEnhanced International Equity Index Fund	7.11%
				ŸInternational Opportunities Fund	6.67%
				ŸEmerging Markets Equity Fund	4.92%
				ŸGlobal Natural Resources Fund	1.35%
FIXED-INCOME	9.87%	Fixed-Income	9.87%	ŸHigh-Yield Fund	4.97%
				ŸBond Plus Fund	3.92%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

TIAA-CREF Lifecycle 2060 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.84%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.43%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.74%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

591

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,138

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 2,633

TIAA-CREF Lifecycle 2060 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.57%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.26%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.67%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.59%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 60

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

545

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,057

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 2,465

TIAA-CREF Lifecycle 2060 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.54%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.08%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.64%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.44%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 45

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

493

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

967

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 2,279

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

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TIAA-CREF Lifecycle 2055 Fund

TIAA-CREF Lifecycle 2055 Fund

Investment objective

The Lifecycle 2055 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2055 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2055 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.36%	0.11%	0.11%
Acquired Fund Fees and Expenses	[2]	0.44%	0.44%	0.44%
Total Annual Fund Operating Expenses		0.95%	0.80%	0.65%
Waivers and Expense Reimbursements	[3],[4]	(0.26%)	(0.21%)	(0.21%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.69%	0.59%	0.44%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2055 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 70	$ 60	$ 45
3 Years	277	234	187
5 Years	500	424	341
10 Years	$ 1,143	$ 970	$ 791

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2055.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2055 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2062 to 2065. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.99%	U.S. Equity	61.97%	ŸLarge-Cap Growth Fund	12.07%
				ŸEnhanced Large-Cap Growth Index Fund	11.78%
				ŸLarge-Cap Value Fund	11.20%
				ŸEnhanced Large-Cap Value Index Fund	10.94%
				ŸGrowth & Income Fund	9.93%
				ŸSmall-Cap Equity Fund	4.90%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.53%
		International Equity	28.02%	ŸInternational Equity Fund	7.84%
				ŸEnhanced International Equity Index Fund	7.23%
				ŸInternational Opportunities Fund	6.65%
				ŸEmerging Markets Equity Fund	4.97%
				ŸGlobal Natural Resources Fund	1.33%
FIXED-INCOME	10.01%	Fixed-Income	10.00%	ŸHigh-Yield Fund	5.00%
				ŸBond Plus Fund	4.02%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2055 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.16%.

Best quarter: 12.82%, for the quarter ended March 31, 2012. Worst quarter: -4.50%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2055 Fund		One Year	Since Inception		Inception Date
Retirement Class		4.37%	8.80%		Apr. 29, 2011
Institutional Class		4.58%	9.07%		Apr. 29, 2011
Premier Class		4.39%	8.89%		Apr. 29, 2011
After Taxes on Distributions | Retirement Class		3.04%	7.78%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.05%	6.64%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	13.91%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	3.81%	[1]
Lifecycle 2055 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.30%	9.81%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2055 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle Retirement Income Fund

TIAA-CREF Lifecycle Retirement Income Fund

Investment objective

The Lifecycle Retirement Income Fund seeks high total return over time primarily through income,

with a secondary emphasis on capital appreciation.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Retirement Income Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Retirement Income Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.25%	0.05%	0.15%
Other Expenses		0.08%	0.30%	0.05%	0.05%
Acquired Fund Fees and Expenses	[2]	0.36%	0.36%	0.36%	0.36%
Total Annual Fund Operating Expenses		0.79%	0.81%	0.66%	0.51%
Waivers and Expense Reimbursements	[3],[4]	(0.18%)	(0.20%)	(0.15%)	(0.15%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.61%	0.61%	0.51%	0.36%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016 but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Retirement Income Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 62	$ 62	$ 52	$ 37
3 Years	234	239	196	148
5 Years	421	430	353	270
10 Years	$ 961	$ 983	$ 808	$ 626

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 19% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy that will not gradually adjust over time and is designed for investors who are already in or entering retirement (i.e., have already passed their retirement year).

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 40.00% of the Fund’s assets to equity Underlying Funds and 60.00% of its assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations may be changed and actual allocations may vary up to ten percentage points from the targets. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which may change, are approximately as follows: U.S. Equity: 28%; International Equity: 12%; Fixed-Income: 40%; Short-Term Fixed-Income: 10%; and Inflation-Protected Assets: 10%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change. Investors should note that the Fund has a significant level of equity exposure and this exposure could cause fluctuation in the value of the Fund depending on the performance of the equity markets generally.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	40.26%	U.S. Equity	27.19%	ŸLarge-Cap Growth Fund	5.44%
				ŸEnhanced Large-Cap Growth Index Fund	5.12%
				ŸLarge-Cap Value Fund	5.04%
				ŸEnhanced Large-Cap Value Index Fund	4.75%
				ŸGrowth & Income Fund	4.47%
				ŸSmall-Cap Equity Fund	2.18%
				ŸMid-Cap Growth Fund	0.11%
				ŸMid-Cap Value Fund	0.08%
		International Equity	13.07%	ŸInternational Equity Fund	3.78%
				ŸEnhanced International Equity Index Fund	3.18%
				ŸInternational Opportunities Fund	3.00%
				ŸEmerging Markets Equity Fund	2.51%
				ŸGlobal Natural Resources Fund	0.60%
FIXED-INCOME	59.74%	Fixed-Income	39.78%	ŸBond Fund	24.85%
				ŸBond Plus Fund	10.95%
				ŸHigh-Yield Fund	2.99%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	10.01%	ŸShort-Term Bond Fund	10.00%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	9.95%	ŸInflation-Linked Bond Fund	9.95%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional, Retail and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Retirement Income Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.07%.

Best quarter: 8.88%, for the quarter ended September 30, 2009. Worst quarter: -7.81%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Retirement Income Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		4.18%	7.54%	4.63%		Nov. 30, 2007
Institutional Class		4.53%	7.81%	4.89%		Nov. 30, 2007
Retail Class		4.18%	7.56%	4.71%		Nov. 30, 2007
Premier Class		4.38%	7.66%	4.71%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.82%	6.49%	3.58%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		2.71%	5.58%	3.25%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.76%	[2]
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.35%	[2]
Lifecycle Retirement Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[3]	5.86%	7.63%	5.09%	[2]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retail Class shares; (ii) 0.25% of average daily net assets for Retirement Class shares; (iii) 0.15% of average daily net assets for Premier Class shares; and (iv) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

[2] Performance is calculated from the inception date of the Retirement Class.

[3] As of the close of business on December 31, 2014, the Lifecycle Retirement Income Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 12.0% MSCI All Country World Index ex USA; 10.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2055 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2055 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2055 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

9.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2055. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2055 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2062 to 2065. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.99%	U.S. Equity	63.21%	ŸEquity Index Fund	63.21%
		International Equity	26.78%	ŸInternational Equity Index Fund	20.58%
				ŸEmerging Markets Equity Index Fund	6.20%
FIXED-INCOME	10.01%	Fixed-Income	10.01%	ŸBond Index Fund	10.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2055 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2055 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.56%.

Bar Chart Closing [Text Block]

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Best quarter: 11.36%, for the quarter ended March 31, 2012. Worst quarter: -3.64%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.56%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.36%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(3.64%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2055 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

13.91%

^[1]

TIAA-CREF Lifecycle Index 2055 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

3.81%

^[1]

TIAA-CREF Lifecycle Index 2055 Fund | Lifecycle Index 2055 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.18%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

9.79%

^[1],[2]

TIAA-CREF Lifecycle Index 2055 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.50%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.72%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.35%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

195

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

366

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 862

Annual Return 2012

rr_AnnualReturn2012

15.36%

Annual Return 2013

rr_AnnualReturn2013

24.93%

Annual Return 2014

rr_AnnualReturn2014

6.62%

One Year

rr_AverageAnnualReturnYear01

6.62%

Since Inception

rr_AverageAnnualReturnSinceInception

9.33%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

TIAA-CREF Lifecycle Index 2055 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.98%

Since Inception

rr_AverageAnnualReturnSinceInception

8.81%

TIAA-CREF Lifecycle Index 2055 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.08%

Since Inception

rr_AverageAnnualReturnSinceInception

7.24%

TIAA-CREF Lifecycle Index 2055 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.24%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.56%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.29%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

150

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

284

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 674

One Year

rr_AverageAnnualReturnYear01

6.73%

Since Inception

rr_AverageAnnualReturnSinceInception

9.45%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

TIAA-CREF Lifecycle Index 2055 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.24%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.41%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.29%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

102

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

201

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 489

One Year

rr_AverageAnnualReturnYear01

6.86%

Since Inception

rr_AverageAnnualReturnSinceInception

9.60%

Inception Date

rr_AverageAnnualReturnInceptionDate

Apr. 29, 2011

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2055 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

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TIAA-CREF Lifestyle Aggressive Growth Fund

TIAA-CREF Lifestyle Aggressive Growth Fund

Investment objective

The Fund seeks long-term growth of capital.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifestyle Aggressive Growth Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifestyle Aggressive Growth Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees		0.25%		0.15%
Other Expenses		0.31%	0.49%	0.25%	0.25%
Acquired Fund Fees and Expenses	[1]	0.45%	0.45%	0.45%	0.45%
Total Annual Fund Operating Expenses		1.11%	1.04%	0.95%	0.80%
Waivers and Expense Reimbursements	[2]	(0.24%)	(0.24%)	(0.25%)	(0.25%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.87%	0.80%	0.70%	0.55%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifestyle Aggressive Growth Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 89	$ 82	$ 72	$ 56
3 Years	329	307	278	230
5 Years	588	551	501	420
10 Years	$ 1,330	$ 1,249	$ 1,144	$ 967

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term growth of capital through a relatively stable asset allocation strategy targeting an aggressive growth risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 100% of the Fund’s assets in equity Underlying Funds and (2) approximately 0% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	99.99%	U.S. Equity	69.21%	ŸLarge-Cap Growth Fund	18.01%
				ŸLarge-Cap Value Fund	16.60%
				ŸGrowth & Income Fund	14.78%
				ŸEnhanced Large-Cap Growth Index Fund	6.41%
				ŸEnhanced Large-Cap Value Index Fund	5.96%
				ŸSmall-Cap Equity Fund	5.46%
				ŸMid-Cap Growth Fund	1.06%
				ŸMid-Cap Value Fund	0.93%
		International Equity	30.78%	ŸInternational Equity Fund	10.21%
				ŸInternational Opportunities Fund	7.38%
				ŸEnhanced International Equity Index Fund	6.31%
				ŸEmerging Markets Equity Fund	5.39%
				ŸGlobal Natural Resources Fund	1.49%
FIXED-INCOME	0.01%	Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a significantly higher percentage of equity Underlying Funds, Equity Underlying Fund Risks are expected to predominate.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

·foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Aggressive Growth Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.79%.

Best quarter: 14.33%, for the quarter ended March 31, 2012. Worst quarter: -5.47%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifestyle Aggressive Growth Fund		One Year	Since Inception		Inception Date
Institutional Class		4.51%	16.67%		Dec. 09, 2011
Retail Class		4.23%	16.30%		Dec. 09, 2011
Retirement Class		4.26%	16.39%		Dec. 09, 2011
Premier Class		4.37%	16.51%		Dec. 09, 2011
After Taxes on Distributions | Institutional Class		3.02%	15.43%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.33%	12.91%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	20.13%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	2.86%	[1]
Lifestyle Aggressive Growth Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.42%	16.57%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Aggressive Growth Fund Composite Index consisted of: 70.0% Russell 3000 Index; and 30.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle Index 2045 Fund

TIAA-CREF Lifecycle Index 2045 Fund

Investment objective

The Lifecycle Index 2045 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2045 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2045 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.30%	0.05%	0.05%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		0.52%	0.37%	0.22%
Waivers and Expense Reimbursements	[3],[4]	(0.15%)	(0.10%)	(0.10%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2045 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	152	109	61
5 Years	276	198	114
10 Years	$ 638	$ 458	$ 270

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2045. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2045 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2052 to 2055. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.97%	U.S. Equity	63.15%	ŸEquity Index Fund	63.15%
		International Equity	26.82%	ŸInternational Equity Index Fund	20.61%
				ŸEmerging Markets Equity Index Fund	6.21%
FIXED-INCOME	10.03%	Fixed-Income	10.03%	ŸBond Index Fund	10.03%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2045 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.60%.

Best quarter: 11.95%, for the quarter ended September 30, 2010. Worst quarter: -14.77%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2045 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.56%	11.38%	11.69%		Sep. 30, 2009
Institutional Class		6.85%	11.66%	11.97%		Sep. 30, 2009
Premier Class		6.73%	11.50%	11.81%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.93%	10.92%	11.22%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		4.05%	9.03%	9.31%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2045 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.18%	11.84%	12.17%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2045 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle Index 2050 Fund

TIAA-CREF Lifecycle Index 2050 Fund

Investment objective

The Lifecycle Index 2050 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2050 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2050 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.32%	0.07%	0.07%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		0.54%	0.39%	0.24%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2050 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	156	113	65
5 Years	285	207	123
10 Years	$ 661	$ 481	$ 294

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2050. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2050 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2057 to 2060. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.00%	U.S. Equity	63.24%	ŸEquity Index Fund	63.24%
		International Equity	26.76%	ŸInternational Equity Index Fund	20.56%
				ŸEmerging Markets Equity Index Fund	6.20%
FIXED-INCOME	10.00%	Fixed-Income	10.00%	ŸBond Index Fund	10.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2050 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.67%.

Best quarter: 11.85%, for the quarter ended September 30, 2010. Worst quarter: -14.85%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2050 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.53%	11.37%	11.69%		Sep. 30, 2009
Institutional Class		6.80%	11.65%	11.97%		Sep. 30, 2009
Premier Class		6.68%	11.49%	11.81%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.88%	10.90%	11.21%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		4.03%	9.02%	9.31%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2050 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.18%	11.84%	12.17%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2050 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle 2050 Fund

TIAA-CREF Lifecycle 2050 Fund

Investment objective

The Lifecycle 2050 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2050 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2050 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.44%	0.44%	0.44%
Total Annual Fund Operating Expenses		0.87%	0.72%	0.57%
Waivers and Expense Reimbursements	[3],[4]	(0.18%)	(0.13%)	(0.13%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.69%	0.59%	0.44%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2050 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 70	$ 60	$ 45
3 Years	260	217	170
5 Years	465	388	305
10 Years	$ 1,056	$ 882	$ 701

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 7% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2050.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2050 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2057 to 2060. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.02%	U.S. Equity	62.05%	ŸLarge-Cap Growth Fund	12.13%
				ŸEnhanced Large-Cap Growth Index Fund	11.78%
				ŸLarge-Cap Value Fund	11.20%
				ŸEnhanced Large-Cap Value Index Fund	10.94%
				ŸGrowth & Income Fund	9.96%
				ŸSmall-Cap Equity Fund	4.90%
				ŸMid-Cap Growth Fund	0.61%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.97%	ŸInternational Equity Fund	7.83%
				ŸEnhanced International Equity Index Fund	7.18%
				ŸInternational Opportunities Fund	6.64%
				ŸEmerging Markets Equity Fund	4.98%
				ŸGlobal Natural Resources Fund	1.34%
FIXED-INCOME	9.98%	Fixed-Income	9.98%	ŸHigh-Yield Fund	4.98%
				ŸBond Plus Fund	4.02%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2050 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.20%.

Best quarter: 17.30%, for the quarter ended June 30, 2009. Worst quarter: -21.79%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2050 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		4.26%	11.25%	4.10%		Nov. 30, 2007
Institutional Class		4.59%	11.53%	4.37%		Nov. 30, 2007
Premier Class		4.47%	11.37%	4.18%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.82%	10.33%	3.28%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.07%	8.76%	3.00%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.35%	[2]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.76%	[2]
Lifecycle 2050 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[3]	7.30%	11.85%	5.15%	[2]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

[2] Performance is calculated from the inception date of the Retirement Class.

[3] As of the close of business on December 31, 2014, the Lifecycle 2050 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2015 Fund

Risk/Return:

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Risk/Return [Heading]

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TIAA-CREF Lifecycle 2015 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Lifecycle 2015 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

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Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 16% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

16.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2015.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 50.00% of the Fund’s assets to equity Underlying Funds and 50.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2015 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2022 to 2025. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 34.30%; International Equity: 14.70%; Fixed-Income:38.20%; Short-Term Fixed-Income: 6.40%; and Inflation-Protected Assets: 6.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	50.36%	U.S. Equity	34.29%	ŸLarge-Cap Growth Fund	6.77%
				ŸEnhanced Large-Cap Growth Index Fund	6.49%
				ŸLarge-Cap Value Fund	6.26%
				ŸEnhanced Large-Cap Value Index Fund	6.05%
				ŸGrowth & Income Fund	5.63%
				ŸSmall-Cap Equity Fund	2.71%
				ŸMid-Cap Growth Fund	0.21%
				ŸMid-Cap Value Fund	0.17%
		International Equity	16.07%	ŸInternational Equity Fund	4.56%
				ŸEnhanced International Equity Index Fund	3.99%
				ŸInternational Opportunities Fund	3.75%
				ŸEmerging Markets Equity Fund	3.02%
				ŸGlobal Natural Resources Fund	0.75%
FIXED-INCOME	49.64%	Fixed-Income	37.72%	ŸBond Fund	22.87%
				ŸBond Plus Fund	10.89%
				ŸHigh-Yield Fund	2.97%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	5.92%	ŸShort-Term Bond Fund	5.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	6.00%	ŸInflation-Linked Bond Fund	6.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle 2015 Fund Composite Index consisted of: 37.6% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000® Index; 15.2% MSCI All Country World Index ex USA; 5.8% Barclays U.S. 1–3 Year Government/Credit Bond Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2015 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.57%.

Bar Chart Closing [Text Block]

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Best quarter: 12.39%, for the quarter ended June 30, 2009. Worst quarter: -12.97%, for the quarter ended December 31, 2008.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

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2.57%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

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12.39%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

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(12.97%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

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AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2015 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2015 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2015 Fund | Lifecycle 2015 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

6.36%

^[1]

Five Years

rr_AverageAnnualReturnYear05

8.88%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

5.70%

^[1]

TIAA-CREF Lifecycle 2015 Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

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none

Maximum Deferred Sales Charge

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none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

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none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

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0.05%

^[2]

Other Expenses

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0.27%

Acquired Fund Fees and Expenses

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0.38%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.80%

Waivers and Expense Reimbursements

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(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.63%

Expense Example, with Redemption, 1 Year

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$ 64

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

238

Expense Example, with Redemption, 5 Years

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427

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 974

Annual Return 2005

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4.23%

Annual Return 2006

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9.40%

Annual Return 2007

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9.46%

Annual Return 2008

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(26.94%)

Annual Return 2009

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21.32%

Annual Return 2010

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12.36%

Annual Return 2011

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0.46%

Annual Return 2012

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13.31%

Annual Return 2013

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13.66%

Annual Return 2014

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4.45%

One Year

rr_AverageAnnualReturnYear01

4.45%

Five Years

rr_AverageAnnualReturnYear05

8.71%

Ten Years

rr_AverageAnnualReturnYear10

5.32%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2015 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

2.56%

Five Years

rr_AverageAnnualReturnYear05

7.37%

Ten Years

rr_AverageAnnualReturnYear10

4.29%

TIAA-CREF Lifecycle 2015 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.45%

Five Years

rr_AverageAnnualReturnYear05

6.61%

Ten Years

rr_AverageAnnualReturnYear10

3.98%

TIAA-CREF Lifecycle 2015 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

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0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.38%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.65%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.53%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 54

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

196

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

350

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 799

One Year

rr_AverageAnnualReturnYear01

4.63%

Five Years

rr_AverageAnnualReturnYear05

8.82%

Ten Years

rr_AverageAnnualReturnYear10

5.38%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2015 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.38%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.50%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.38%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 39

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

148

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

268

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 617

One Year

rr_AverageAnnualReturnYear01

4.78%

Five Years

rr_AverageAnnualReturnYear05

8.99%

Ten Years

rr_AverageAnnualReturnYear10

5.54%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2015 Fund Composite Index consisted of: 37.6% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000 Index; 15.2% MSCI All Country World Index ex USA; 5.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2025 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2025 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Lifecycle 2025 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

12.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2025.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 66.00% of the Fund’s assets to equity Underlying Funds and 34.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2025 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2032 to 2035. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 45.08%; International Equity: 19.32%; Fixed-Income: 30.80%; Short-Term Fixed-Income: 2.4%; and Inflation-Protected Assets: 2.4%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	66.30%	U.S. Equity	45.50%	ŸLarge-Cap Growth Fund	8.92%
				ŸEnhanced Large-Cap Growth Index Fund	8.62%
				ŸLarge-Cap Value Fund	8.29%
				ŸEnhanced Large-Cap Value Index Fund	8.03%
				ŸGrowth & Income Fund	7.37%
				ŸSmall-Cap Equity Fund	3.58%
				ŸMid-Cap Growth Fund	0.37%
				ŸMid-Cap Value Fund	0.32%
		International Equity	20.80%	ŸInternational Equity Fund	5.86%
				ŸEnhanced International Equity Index Fund	5.23%
				ŸInternational Opportunities Fund	4.95%
				ŸEmerging Markets Equity Fund	3.75%
				ŸGlobal Natural Resources Fund	1.01%
FIXED-INCOME	33.70%	Fixed-Income	29.79%	ŸBond Fund	13.98%
				ŸBond Plus Fund	10.83%
				ŸHigh-Yield Fund	3.99%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	1.93%	ŸShort-Term Bond Fund	1.92%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	1.98%	ŸInflation-Linked Bond Fund	1.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle 2025 Fund Composite Index consisted of: 46.8% Russell 3000® Index; 29.6% Barclays U.S. Aggregate Bond Index; 20.0% MSCI All Country World Index ex USA; 1.8% Barclays U.S. 1–3 Year Government/Credit Bond Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2025 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.18%.

Bar Chart Closing [Text Block]

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Best quarter: 15.33%, for the quarter ended June 30, 2009. Worst quarter: -16.97%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

3.18%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

15.33%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(16.97%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2025 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2025 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2025 Fund | Lifecycle 2025 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.89%

^[1]

Five Years

rr_AverageAnnualReturnYear05

10.25%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

5.88%

^[1]

TIAA-CREF Lifecycle 2025 Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.41%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.83%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.66%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 67

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

248

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

444

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,010

Annual Return 2005

rr_AnnualReturn2005

5.07%

Annual Return 2006

rr_AnnualReturn2006

10.78%

Annual Return 2007

rr_AnnualReturn2007

9.33%

Annual Return 2008

rr_AnnualReturn2008

(33.48%)

Annual Return 2009

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24.96%

Annual Return 2010

rr_AnnualReturn2010

13.88%

Annual Return 2011

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(1.56%)

Annual Return 2012

rr_AnnualReturn2012

15.24%

Annual Return 2013

rr_AnnualReturn2013

19.12%

Annual Return 2014

rr_AnnualReturn2014

4.56%

One Year

rr_AverageAnnualReturnYear01

4.56%

Five Years

rr_AverageAnnualReturnYear05

9.98%

Ten Years

rr_AverageAnnualReturnYear10

5.46%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2025 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.81%

Five Years

rr_AverageAnnualReturnYear05

8.76%

Ten Years

rr_AverageAnnualReturnYear10

4.54%

TIAA-CREF Lifecycle 2025 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.46%

Five Years

rr_AverageAnnualReturnYear05

7.68%

Ten Years

rr_AverageAnnualReturnYear10

4.14%

TIAA-CREF Lifecycle 2025 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.41%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.68%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.56%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 57

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

205

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

367

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 835

One Year

rr_AverageAnnualReturnYear01

4.73%

Five Years

rr_AverageAnnualReturnYear05

10.06%

Ten Years

rr_AverageAnnualReturnYear10

5.51%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2025 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.41%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.53%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.41%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 42

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

158

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

284

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 653

One Year

rr_AverageAnnualReturnYear01

4.87%

Five Years

rr_AverageAnnualReturnYear05

10.23%

Ten Years

rr_AverageAnnualReturnYear10

5.67%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2025 Fund Composite Index consisted of: 46.8% Russell 3000 Index; 29.6% Barclays U.S. Aggregate Bond Index; 20.0% MSCI All Country World Index ex USA; 1.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 1.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

TIAA-CREF Lifecycle Index 2015 Fund

TIAA-CREF Lifecycle Index 2015 Fund

Investment objective

The Lifecycle Index 2015 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2015 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2015 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.29%	0.04%	0.04%
Acquired Fund Fees and Expenses	[2]	0.10%	0.10%	0.10%
Total Annual Fund Operating Expenses		0.54%	0.39%	0.24%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2015 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	156	113	65
5 Years	285	207	123
10 Years	$ 661	$ 481	$ 294

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 12% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2015. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 50.00% of the Fund’s assets to equity Underlying Funds and 50.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2015 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2022 to 2025. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 34.30%; International Equity: 14.70%; Fixed-Income: 38.20%; Short-Term Fixed-Income: 6.40%; and Inflation-Protected Assets: 6.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	50.15%	U.S. Equity	35.29%	ŸEquity Index Fund	35.29%
		International Equity	14.86%	ŸInternational Equity Index Fund	11.42%
				ŸEmerging Markets Equity Index Fund	3.44%
FIXED-INCOME	49.85%	Fixed-Income	43.92%	ŸBond Index Fund	43.92%
		Inflation-Protected Assets	5.93%	ŸInflation-Linked Bond Fund	5.93%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2015 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.42%.

Best quarter: 8.63%, for the quarter ended September 30, 2010. Worst quarter: -8.09%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2015 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.07%	8.53%	8.69%		Sep. 30, 2009
Institutional Class		6.40%	8.81%	8.97%		Sep. 30, 2009
Premier Class		6.19%	8.64%	8.80%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.33%	7.95%	8.12%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.63%	6.57%	6.72%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2015 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.59%	8.99%	9.17%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.08%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.27% of average daily net assets for Retirement Class shares; (ii) 0.17% of average daily net assets for Premier Class shares; and (iii) 0.02% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2015 Fund Composite Index consisted of: 43.4% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000 Index; 15.2% MSCI EAFE + Emerging Markets Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2050 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2050 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2050 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

5.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2050. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2050 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2057 to 2060. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.00%	U.S. Equity	63.24%	ŸEquity Index Fund	63.24%
		International Equity	26.76%	ŸInternational Equity Index Fund	20.56%
				ŸEmerging Markets Equity Index Fund	6.20%
FIXED-INCOME	10.00%	Fixed-Income	10.00%	ŸBond Index Fund	10.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2050 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2050 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.67%.

Bar Chart Closing [Text Block]

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Best quarter: 11.85%, for the quarter ended September 30, 2010. Worst quarter: -14.85%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.67%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.85%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.85%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2050 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2050 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2050 Fund | Lifecycle Index 2050 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.18%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.84%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

12.17%

^[1],[2]

TIAA-CREF Lifecycle Index 2050 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.32%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.54%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

156

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

285

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 661

Annual Return 2010

rr_AnnualReturn2010

13.51%

Annual Return 2011

rr_AnnualReturn2011

(1.70%)

Annual Return 2012

rr_AnnualReturn2012

15.39%

Annual Return 2013

rr_AnnualReturn2013

24.88%

Annual Return 2014

rr_AnnualReturn2014

6.53%

One Year

rr_AverageAnnualReturnYear01

6.53%

Five Years

rr_AverageAnnualReturnYear05

11.37%

Since Inception

rr_AverageAnnualReturnSinceInception

11.69%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2050 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.88%

Five Years

rr_AverageAnnualReturnYear05

10.90%

Since Inception

rr_AverageAnnualReturnSinceInception

11.21%

TIAA-CREF Lifecycle Index 2050 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.03%

Five Years

rr_AverageAnnualReturnYear05

9.02%

Since Inception

rr_AverageAnnualReturnSinceInception

9.31%

TIAA-CREF Lifecycle Index 2050 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.39%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

113

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

207

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 481

One Year

rr_AverageAnnualReturnYear01

6.68%

Five Years

rr_AverageAnnualReturnYear05

11.49%

Since Inception

rr_AverageAnnualReturnSinceInception

11.81%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2050 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.07%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.24%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

65

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

123

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 294

One Year

rr_AverageAnnualReturnYear01

6.80%

Five Years

rr_AverageAnnualReturnYear05

11.65%

Since Inception

rr_AverageAnnualReturnSinceInception

11.97%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2050 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle Index 2010 Fund

TIAA-CREF Lifecycle Index 2010 Fund

Investment objective

The Lifecycle Index 2010 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2010 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2010 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.32%	0.07%	0.07%
Acquired Fund Fees and Expenses	[2]	0.11%	0.11%	0.11%
Total Annual Fund Operating Expenses		0.58%	0.43%	0.28%
Waivers and Expense Reimbursements	[3],[4]	(0.21%)	(0.16%)	(0.16%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2010 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	165	122	74
5 Years	303	225	141
10 Years	$ 706	$ 527	$ 340

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have recently retired or have an approximate target retirement year within a few years, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors who retired in 2010 or plan to retire within a few years of 2010. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 45.00% of the Fund’s assets to equity Underlying Funds and 55.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative. The Fund had target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2010 and will reach the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2017 to 2020. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 30.80%; International Equity: 13.20%; Fixed-Income: 39.20%; Short-Term Fixed-Income: 8.40%; and Inflation-Protected Assets: 8.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	45.11%	U.S. Equity	31.75%	ŸEquity Index Fund	31.75%
		International Equity	13.36%	ŸInternational Equity Index Fund	10.27%
				ŸEmerging Markets Equity Index Fund	3.09%
FIXED-INCOME	54.89%	Fixed-Income	46.94%	ŸBond Index Fund	46.94%
		Inflation-Protected Assets	7.95%	ŸInflation-Linked Bond Fund	7.95%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2010 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.25%.

Best quarter: 7.77%, for the quarter ended September 30, 2010. Worst quarter: -6.63%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2010 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		5.98%	8.01%	8.13%		Sep. 30, 2009
Institutional Class		6.31%	8.30%	8.42%		Sep. 30, 2009
Premier Class		6.09%	8.14%	8.25%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.20%	7.37%	7.50%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.57%	6.12%	6.23%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Lifecycle Index 2010 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.47%	8.47%	8.60%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.09%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.26% of average daily net assets for Retirement Class shares; (ii) 0.16% of average daily net assets for Premier Class shares; and (iii) 0.01% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2010 Fund Composite Index consisted of: 46.7% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000 Index; 13.7% MSCI EAFE + Emerging Markets Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifestyle Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifestyle Growth Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term growth of capital with some current income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term growth of capital with some current income through a relatively stable asset allocation strategy targeting a growth-oriented risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 80% of the Fund’s assets in equity Underlying Funds and (2) approximately 20% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	80.04%	U.S. Equity	55.26%	ŸLarge-Cap Growth Fund	14.41%
				ŸLarge-Cap Value Fund	13.36%
				ŸGrowth & Income Fund	11.85%
				ŸEnhanced Large-Cap Growth Index Fund	5.10%
				ŸEnhanced Large-Cap Value Index Fund	4.72%
				ŸSmall-Cap Equity Fund	4.34%
				ŸMid-Cap Growth Fund	0.79%
				ŸMid-Cap Value Fund	0.69%
		International Equity	24.78%	ŸInternational Equity Fund	8.17%
				ŸInternational Opportunities Fund	5.93%
				ŸEnhanced International Equity Index Fund	5.06%
				ŸEmerging Markets Equity Fund	4.43%
				ŸGlobal Natural Resources Fund	1.19%
FIXED-INCOME	19.96%	Fixed-Income	19.96%	ŸBond Plus Fund	18.93%
				ŸHigh-Yield Fund	1.03%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a higher percentage of equity Underlying Funds, Equity Underlying Fund Risks are expected to predominate.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifestyle Growth Fund Composite Index consisted of: 56.0% Russell 3000® Index; 24.0% MSCI All Country World Index ex USA; and 20.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Growth Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.02%.

Bar Chart Closing [Text Block]

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Best quarter: 11.87%, for the quarter ended March 31, 2012. Worst quarter: -3.87%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.02%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.87%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(3.87%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifestyle Growth Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

20.13%

^[1]

TIAA-CREF Lifestyle Growth Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

2.86%

^[1]

TIAA-CREF Lifestyle Growth Fund | Lifestyle Growth Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.18%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

13.79%

^[1],[2]

TIAA-CREF Lifestyle Growth Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.24%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.02%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.82%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 84

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

305

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

544

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,230

One Year

rr_AverageAnnualReturnYear01

4.42%

Since Inception

rr_AverageAnnualReturnSinceInception

13.90%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Growth Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.45%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.98%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.78%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 80

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

292

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

522

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,183

One Year

rr_AverageAnnualReturnYear01

4.43%

Since Inception

rr_AverageAnnualReturnSinceInception

13.95%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Growth Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

Other Expenses

rr_OtherExpensesOverAssets

0.21%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.89%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.68%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 69

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

263

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

472

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,077

One Year

rr_AverageAnnualReturnYear01

4.58%

Since Inception

rr_AverageAnnualReturnSinceInception

14.07%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Growth Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.21%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.43%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.74%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.53%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 54

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

215

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

391

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 899

Annual Return 2012

rr_AnnualReturn2012

17.26%

Annual Return 2013

rr_AnnualReturn2013

23.06%

Annual Return 2014

rr_AnnualReturn2014

4.73%

One Year

rr_AverageAnnualReturnYear01

4.73%

Since Inception

rr_AverageAnnualReturnSinceInception

14.24%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Growth Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.32%

Since Inception

rr_AverageAnnualReturnSinceInception

13.02%

TIAA-CREF Lifestyle Growth Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.26%

Since Inception

rr_AverageAnnualReturnSinceInception

10.88%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Growth Fund Composite Index consisted of: 56.0% Russell 3000 Index; 24.0% MSCI All Country World Index ex USA; and 20.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2035 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2035 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2035 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

5.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2035. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 82.00% of the Fund’s assets to equity Underlying Funds and 18.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2035 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2042 to 2045. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 56.28%; International Equity: 24.12%; Fixed-Income: 19.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	82.03%	U.S. Equity	57.76%	ŸEquity Index Fund	57.76%
		International Equity	24.27%	ŸInternational Equity Index Fund	18.65%
				ŸEmerging Markets Equity Index Fund	5.62%
FIXED-INCOME	17.97%	Fixed-Income	17.97%	ŸBond Index Fund	17.97%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2035 Fund Composite Index consisted of: 58.0% Russell 3000® Index; 24.8% MSCI EAFE + Emerging Markets Index; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2035 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.44%.

Bar Chart Closing [Text Block]

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Best quarter: 11.89%, for the quarter ended September 30, 2010. Worst quarter: -14.45%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.44%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.89%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(14.45%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2035 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2035 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2035 Fund | Lifecycle Index 2035 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.11%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.50%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

11.85%

^[1],[2]

TIAA-CREF Lifecycle Index 2035 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.50%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

147

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

267

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 616

Annual Return 2010

rr_AnnualReturn2010

13.41%

Annual Return 2011

rr_AnnualReturn2011

(1.49%)

Annual Return 2012

rr_AnnualReturn2012

15.06%

Annual Return 2013

rr_AnnualReturn2013

23.22%

Annual Return 2014

rr_AnnualReturn2014

6.51%

One Year

rr_AverageAnnualReturnYear01

6.51%

Five Years

rr_AverageAnnualReturnYear05

11.03%

Since Inception

rr_AverageAnnualReturnSinceInception

11.36%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2035 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.87%

Five Years

rr_AverageAnnualReturnYear05

10.55%

Since Inception

rr_AverageAnnualReturnSinceInception

10.89%

TIAA-CREF Lifecycle Index 2035 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

4.00%

Five Years

rr_AverageAnnualReturnYear05

8.72%

Since Inception

rr_AverageAnnualReturnSinceInception

9.03%

TIAA-CREF Lifecycle Index 2035 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.35%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.08%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

104

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

188

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 435

One Year

rr_AverageAnnualReturnYear01

6.68%

Five Years

rr_AverageAnnualReturnYear05

11.15%

Since Inception

rr_AverageAnnualReturnSinceInception

11.48%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2035 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.20%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.08%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

56

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

105

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 247

One Year

rr_AverageAnnualReturnYear01

6.80%

Five Years

rr_AverageAnnualReturnYear05

11.31%

Since Inception

rr_AverageAnnualReturnSinceInception

11.65%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2035 Fund Composite Index consisted of: 58.0% Russell 3000 Index; 24.8% MSCI EAFE + Emerging Markets Index; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2045 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2045 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2045 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

5.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2045. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2045 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2052 to 2055. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.97%	U.S. Equity	63.15%	ŸEquity Index Fund	63.15%
		International Equity	26.82%	ŸInternational Equity Index Fund	20.61%
				ŸEmerging Markets Equity Index Fund	6.21%
FIXED-INCOME	10.03%	Fixed-Income	10.03%	ŸBond Index Fund	10.03%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle Index 2045 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2045 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.60%.

Bar Chart Closing [Text Block]

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Best quarter: 11.95%, for the quarter ended September 30, 2010. Worst quarter: -14.77%, for the quarter ended September 30, 2011.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

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Jun. 30, 2015

Bar Chart, Year to Date Return

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2.60%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

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Sep. 30, 2010

Highest Quarterly Return

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11.95%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

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Sep. 30, 2011

Lowest Quarterly Return

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(14.77%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

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AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2045 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2045 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2045 Fund | Lifecycle Index 2045 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

7.18%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.84%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

12.17%

^[1],[2]

TIAA-CREF Lifecycle Index 2045 Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

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none

Maximum Deferred Sales Charge

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none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

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none

Maximum Account Fee

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none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

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0.05%

^[3]

Other Expenses

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0.30%

Acquired Fund Fees and Expenses

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0.07%

^[4]

Total Annual Fund Operating Expenses

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0.52%

Waivers and Expense Reimbursements

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(0.15%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

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$ 38

Expense Example, with Redemption, 3 Years

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152

Expense Example, with Redemption, 5 Years

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276

Expense Example, with Redemption, 10 Years

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$ 638

Annual Return 2010

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13.50%

Annual Return 2011

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(1.61%)

Annual Return 2012

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15.38%

Annual Return 2013

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24.86%

Annual Return 2014

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6.56%

One Year

rr_AverageAnnualReturnYear01

6.56%

Five Years

rr_AverageAnnualReturnYear05

11.38%

Since Inception

rr_AverageAnnualReturnSinceInception

11.69%

Inception Date

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Sep. 30, 2009

TIAA-CREF Lifecycle Index 2045 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

5.93%

Five Years

rr_AverageAnnualReturnYear05

10.92%

Since Inception

rr_AverageAnnualReturnSinceInception

11.22%

TIAA-CREF Lifecycle Index 2045 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

4.05%

Five Years

rr_AverageAnnualReturnYear05

9.03%

Since Inception

rr_AverageAnnualReturnSinceInception

9.31%

TIAA-CREF Lifecycle Index 2045 Fund | Premier Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

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none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

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none

Maximum Account Fee

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none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

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0.15%

^[3]

Other Expenses

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0.05%

Acquired Fund Fees and Expenses

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0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.37%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

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$ 28

Expense Example, with Redemption, 3 Years

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109

Expense Example, with Redemption, 5 Years

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198

Expense Example, with Redemption, 10 Years

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$ 458

One Year

rr_AverageAnnualReturnYear01

6.73%

Five Years

rr_AverageAnnualReturnYear05

11.50%

Since Inception

rr_AverageAnnualReturnSinceInception

11.81%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2045 Fund | Institutional Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

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0.10%

Distribution (Rule 12b-1) Fees

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^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.05%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.22%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.10%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

61

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

114

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 270

One Year

rr_AverageAnnualReturnYear01

6.85%

Five Years

rr_AverageAnnualReturnYear05

11.66%

Since Inception

rr_AverageAnnualReturnSinceInception

11.97%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2045 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

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TIAA-CREF Lifecycle Index 2030 Fund

TIAA-CREF Lifecycle Index 2030 Fund

Investment objective

The Lifecycle Index 2030 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2030 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2030 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.08%	0.08%	0.08%
Total Annual Fund Operating Expenses		0.51%	0.36%	0.21%
Waivers and Expense Reimbursements	[3],[4]	(0.14%)	(0.09%)	(0.09%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2030 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	149	107	58
5 Years	271	193	109
10 Years	$ 627	$ 447	$ 259

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2030. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 74.00% of the Fund’s assets to equity Underlying Funds and 26.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2030 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2037 to 2040. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 50.68%; International Equity: 21.72%; Fixed-Income: 26.80%; Short-Term Fixed-Income: 0.40%; and Inflation-Protected Assets: 0.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	74.02%	U.S. Equity	52.14%	ŸEquity Index Fund	52.14%
		International Equity	21.88%	ŸInternational Equity Index Fund	16.82%
				ŸEmerging Markets Equity Index Fund	5.06%
FIXED-INCOME	25.98%	Fixed-Income	25.98%	ŸBond Index Fund	25.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2030 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.19%.

Best quarter: 11.08%, for the quarter ended September 30, 2010. Worst quarter: -12.86%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2030 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.41%	10.44%	10.74%		Sep. 30, 2009
Institutional Class		6.68%	10.72%	11.01%		Sep. 30, 2009
Premier Class		6.56%	10.55%	10.84%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.74%	9.95%	10.25%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.91%	8.22%	8.48%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2030 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.02%	10.89%	11.20%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.06%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.29% of average daily net assets for Retirement Class shares; (ii) 0.19% of average daily net assets for Premier Class shares; and (iii) 0.04% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2030 Fund Composite Index consisted of: 52.4% Russell 3000 Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI EAFE + Emerging Markets Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Document and Entity Information	Total
Prospectus:
Document Type	485BPOS
Document Period End Date	May 31, 2015
Registrant Name	TIAA-CREF FUNDS
Central Index Key	0001084380
Amendment Flag	false
Document Creation Date	Sep. 25, 2015
Document Effective Date	Oct. 01, 2015
Prospectus Date	Oct. 01, 2015

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2030 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2030 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2030 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

5.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2030. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 74.00% of the Fund’s assets to equity Underlying Funds and 26.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2030 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2037 to 2040. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 50.68%; International Equity: 21.72%; Fixed-Income: 26.80%; Short-Term Fixed-Income: 0.40%; and Inflation-Protected Assets: 0.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	74.02%	U.S. Equity	52.14%	ŸEquity Index Fund	52.14%
		International Equity	21.88%	ŸInternational Equity Index Fund	16.82%
				ŸEmerging Markets Equity Index Fund	5.06%
FIXED-INCOME	25.98%	Fixed-Income	25.98%	ŸBond Index Fund	25.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index 2030 Fund Composite Index consisted of: 52.4% Russell 3000® Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI EAFE + Emerging Markets Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2030 Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.19%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 11.08%, for the quarter ended September 30, 2010. Worst quarter: -12.86%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.19%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

11.08%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(12.86%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index 2030 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index 2030 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index 2030 Fund | Lifecycle Index 2030 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.02%

^[2]

Five Years

rr_AverageAnnualReturnYear05

10.89%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

11.20%

^[1],[2]

TIAA-CREF Lifecycle Index 2030 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.08%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.51%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

149

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

271

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 627

Annual Return 2010

rr_AnnualReturn2010

12.91%

Annual Return 2011

rr_AnnualReturn2011

(0.53%)

Annual Return 2012

rr_AnnualReturn2012

13.98%

Annual Return 2013

rr_AnnualReturn2013

20.63%

Annual Return 2014

rr_AnnualReturn2014

6.41%

One Year

rr_AverageAnnualReturnYear01

6.41%

Five Years

rr_AverageAnnualReturnYear05

10.44%

Since Inception

rr_AverageAnnualReturnSinceInception

10.74%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2030 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.74%

Five Years

rr_AverageAnnualReturnYear05

9.95%

Since Inception

rr_AverageAnnualReturnSinceInception

10.25%

TIAA-CREF Lifecycle Index 2030 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.91%

Five Years

rr_AverageAnnualReturnYear05

8.22%

Since Inception

rr_AverageAnnualReturnSinceInception

8.48%

TIAA-CREF Lifecycle Index 2030 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.08%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.36%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.09%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

107

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

193

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 447

One Year

rr_AverageAnnualReturnYear01

6.56%

Five Years

rr_AverageAnnualReturnYear05

10.55%

Since Inception

rr_AverageAnnualReturnSinceInception

10.84%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index 2030 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.08%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.21%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.09%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

58

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

109

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 259

One Year

rr_AverageAnnualReturnYear01

6.68%

Five Years

rr_AverageAnnualReturnYear05

10.72%

Since Inception

rr_AverageAnnualReturnSinceInception

11.01%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2030 Fund Composite Index consisted of: 52.4% Russell 3000 Index; 25.2% Barclays U.S. Aggregate Bond Index; and 22.4% MSCI EAFE + Emerging Markets Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.06%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.29% of average daily net assets for Retirement Class shares; (ii) 0.19% of average daily net assets for Premier Class shares; and (iii) 0.04% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifestyle Conservative Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifestyle Conservative Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term total return, consisting of current income and capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

13.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term total return, consisting of current income and capital appreciation, through a relatively stable asset allocation strategy targeting a conservative risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 40% of the Fund’s assets in equity Underlying Funds and (2) approximately 60% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	40.15%	U.S. Equity	27.13%	ŸLarge-Cap Growth Fund	7.22%
				ŸLarge-Cap Value Fund	6.69%
				ŸGrowth & Income Fund	5.94%
				ŸEnhanced Large-Cap Growth Index Fund	2.41%
				ŸEnhanced Large-Cap Value Index Fund	2.22%
				ŸSmall-Cap Equity Fund	2.20%
				ŸMid-Cap Growth Fund	0.25%
				ŸMid-Cap Value Fund	0.20%
		International Equity	13.02%	ŸInternational Equity Fund	4.41%
				ŸInternational Opportunities Fund	2.97%
				ŸEnhanced International Equity Index Fund	2.54%
				ŸEmerging Markets Equity Fund	2.51%
				ŸGlobal Natural Resources Fund	0.59%
FIXED-INCOME	59.85%	Fixed-Income	39.92%	ŸBond Plus Fund	29.90%
				ŸBond Fund	9.00%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	19.93%	ŸShort-Term Bond Fund	19.93%
				ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifestyle Conservative Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000® Index; 20.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 12.0% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Conservative Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.36%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 6.70%, for the quarter ended March 31, 2012. Worst quarter: -1.24%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.36%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

6.70%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(1.24%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifestyle Conservative Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

2.86%

^[1]

TIAA-CREF Lifestyle Conservative Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

20.13%

^[1]

TIAA-CREF Lifestyle Conservative Fund | Lifestyle Conservative Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.56%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

7.91%

^[1],[2]

TIAA-CREF Lifestyle Conservative Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.17%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.89%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.75%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 77

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

270

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

479

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,083

One Year

rr_AverageAnnualReturnYear01

4.01%

Since Inception

rr_AverageAnnualReturnSinceInception

8.41%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Conservative Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.40%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.87%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.72%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 74

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

263

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

468

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,059

One Year

rr_AverageAnnualReturnYear01

4.04%

Since Inception

rr_AverageAnnualReturnSinceInception

8.45%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Conservative Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

Other Expenses

rr_OtherExpensesOverAssets

0.16%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.78%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.16%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.62%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 63

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

233

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

418

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 951

One Year

rr_AverageAnnualReturnYear01

4.14%

Since Inception

rr_AverageAnnualReturnSinceInception

8.57%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Conservative Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.15%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.62%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.15%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.47%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 48

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

183

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

331

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 760

Annual Return 2012

rr_AnnualReturn2012

11.78%

Annual Return 2013

rr_AnnualReturn2013

10.84%

Annual Return 2014

rr_AnnualReturn2014

4.28%

One Year

rr_AverageAnnualReturnYear01

4.28%

Since Inception

rr_AverageAnnualReturnSinceInception

8.73%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Conservative Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.01%

Since Inception

rr_AverageAnnualReturnSinceInception

7.60%

TIAA-CREF Lifestyle Conservative Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.72%

Since Inception

rr_AverageAnnualReturnSinceInception

6.40%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Conservative Fund Composite Index consisted of: 40.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 20.0% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 12.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index Retirement Income Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index Retirement Income Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index Retirement Income Fund seeks high total return over time primarily through income,

Objective, Secondary [Text Block]

rr_ObjectiveSecondaryTextBlock

with a secondary emphasis on capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 35% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

35.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016 but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy that will not gradually adjust over time and is designed for investors who are already in or entering retirement (i.e., have already passed their retirement year). The Fund has a policy of investing at least 80% of its assets in Underlying Funds that are managed to seek investment returns that track particular market indices. For purposes of the 80% investment policy, the term “assets” means net assets, plus the amount of any borrowings for investment purposes.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 40.00% of the Fund’s assets to equity Underlying Funds and 60.00% of its assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations may be changed and actual allocations may vary up to ten percentage points from the targets. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which may change, are approximately as follows: U.S. Equity: 28.00%; International Equity: 12.00%; Fixed-Income: 40.00%; Short-Term Fixed-Income: 10.00%; and Inflation-Protected Assets: 10.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income) and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change. Investors should note that the Fund has a significant level of equity exposure and this exposure could cause fluctuation in the value of the Fund depending on the performance of the equity markets generally.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	39.92%	U.S. Equity	28.16%	ŸEquity Index Fund	28.16%
		International Equity	11.76%	ŸInternational Equity Index Fund	9.04%
				ŸEmerging Markets Equity Index Fund	2.72%
FIXED-INCOME	60.08%	Fixed-Income	50.02%	ŸBond Index Fund	50.02%
		Inflation-Protected Assets	10.06%	ŸInflation-Linked Bond Fund	10.06%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle Index Retirement Income Fund Composite Index consisted of: 50.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000® Index; 12.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index Retirement Income Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.16%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 6.74%, for the quarter ended September 30, 2010. Worst quarter: -4.69%, for the quarter ended September 30, 2011.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

1.16%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Sep. 30, 2010

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

6.74%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2011

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(4.69%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle Index Retirement Income Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.27%

^[1]

TIAA-CREF Lifecycle Index Retirement Income Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

16.09%

^[1]

TIAA-CREF Lifecycle Index Retirement Income Fund | Lifecycle Index Retirement Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.34%

^[2]

Five Years

rr_AverageAnnualReturnYear05

7.88%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

7.95%

^[1],[2]

TIAA-CREF Lifecycle Index Retirement Income Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.50%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.76%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.39%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

204

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

384

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 906

Annual Return 2010

rr_AnnualReturn2010

9.70%

Annual Return 2011

rr_AnnualReturn2011

4.21%

Annual Return 2012

rr_AnnualReturn2012

9.33%

Annual Return 2013

rr_AnnualReturn2013

8.16%

Annual Return 2014

rr_AnnualReturn2014

5.84%

One Year

rr_AverageAnnualReturnYear01

5.84%

Five Years

rr_AverageAnnualReturnYear05

7.43%

Since Inception

rr_AverageAnnualReturnSinceInception

7.47%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index Retirement Income Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.01%

Five Years

rr_AverageAnnualReturnYear05

6.71%

Since Inception

rr_AverageAnnualReturnSinceInception

6.75%

TIAA-CREF Lifecycle Index Retirement Income Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.46%

Five Years

rr_AverageAnnualReturnYear05

5.60%

Since Inception

rr_AverageAnnualReturnSinceInception

5.65%

TIAA-CREF Lifecycle Index Retirement Income Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.24%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.60%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.33%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

159

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

302

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 719

One Year

rr_AverageAnnualReturnYear01

5.99%

Five Years

rr_AverageAnnualReturnYear05

7.54%

Since Inception

rr_AverageAnnualReturnSinceInception

7.59%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle Index Retirement Income Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.24%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.11%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.45%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.33%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

111

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

219

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 535

One Year

rr_AverageAnnualReturnYear01

6.15%

Five Years

rr_AverageAnnualReturnYear05

7.69%

Since Inception

rr_AverageAnnualReturnSinceInception

7.74%

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index Retirement Income Fund Composite Index consisted of: 50.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 12.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.09%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.26% of average daily net assets for Retirement Class shares; (ii) 0.16% of average daily net assets for Premier Class shares; and (iii) 0.01% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

Label

Element

Value

TIAA-CREF Lifestyle Moderate Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifestyle Moderate Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term total return, consisting of capital appreciation and current income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

13.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term total return, consisting of capital appreciation and current income, through a relatively stable asset allocation strategy targeting a moderate risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 60% of the Fund’s assets in equity Underlying Funds and (2) approximately 40% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	60.15%	U.S. Equity	41.21%	ŸLarge-Cap Growth Fund	10.83%
				ŸLarge-Cap Value Fund	10.04%
				ŸGrowth & Income Fund	8.91%
				ŸEnhanced Large-Cap Growth Index Fund	3.76%
				ŸEnhanced Large-Cap Value Index Fund	3.47%
				ŸSmall-Cap Equity Fund	3.25%
				ŸMid-Cap Growth Fund	0.51%
				ŸMid-Cap Value Fund	0.44%
		International Equity	18.94%	ŸInternational Equity Fund	6.31%
				ŸInternational Opportunities Fund	4.45%
				ŸEnhanced International Equity Index Fund	3.81%
				ŸEmerging Markets Equity Fund	3.47%
				ŸGlobal Natural Resources Fund	0.90%
FIXED-INCOME	39.85%	Fixed-Income	39.85%	ŸBond Plus Fund	38.83%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifestyle Moderate Fund Composite Index consisted of: 42.0% Russell 3000® Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Moderate Fund

Bar Chart Footnotes [Text Block]

rr_BarChartFootnotesTextBlock

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.23%.

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best quarter: 9.36%, for the quarter ended March 31, 2012. Worst quarter: -2.27%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

3.23%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

9.36%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.27%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifestyle Moderate Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

20.13%

^[1]

TIAA-CREF Lifestyle Moderate Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

2.86%

^[1]

TIAA-CREF Lifestyle Moderate Fund | Lifestyle Moderate Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.92%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

11.03%

^[1],[2]

TIAA-CREF Lifestyle Moderate Fund | Retail Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.15%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.90%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.78%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 80

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

275

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

487

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,097

One Year

rr_AverageAnnualReturnYear01

4.63%

Since Inception

rr_AverageAnnualReturnSinceInception

11.50%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Moderate Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.37%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.87%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.75%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 77

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

266

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

470

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,061

One Year

rr_AverageAnnualReturnYear01

4.74%

Since Inception

rr_AverageAnnualReturnSinceInception

11.57%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Moderate Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

Other Expenses

rr_OtherExpensesOverAssets

0.13%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.78%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.65%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 66

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

236

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

420

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 954

One Year

rr_AverageAnnualReturnYear01

4.92%

Since Inception

rr_AverageAnnualReturnSinceInception

11.69%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Moderate Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.13%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.40%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.63%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.50%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 51

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

189

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

338

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 774

Annual Return 2012

rr_AnnualReturn2012

15.12%

Annual Return 2013

rr_AnnualReturn2013

16.84%

Annual Return 2014

rr_AnnualReturn2014

4.98%

One Year

rr_AverageAnnualReturnYear01

4.98%

Since Inception

rr_AverageAnnualReturnSinceInception

11.86%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Moderate Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.54%

Since Inception

rr_AverageAnnualReturnSinceInception

10.62%

TIAA-CREF Lifestyle Moderate Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.24%

Since Inception

rr_AverageAnnualReturnSinceInception

8.87%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Moderate Fund Composite Index consisted of: 42.0% Russell 3000 Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

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TIAA-CREF Lifecycle 2020 Fund

TIAA-CREF Lifecycle 2020 Fund

Investment objective

The Lifecycle 2020 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2020 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2020 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.39%	0.39%	0.39%
Total Annual Fund Operating Expenses		0.81%	0.66%	0.51%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.64%	0.54%	0.39%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2020 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 65	$ 55	$ 40
3 Years	242	199	151
5 Years	433	356	273
10 Years	$ 986	$ 811	$ 629

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2020.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 58.00% of the Fund’s assets to equity Underlying Funds and 42.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2020 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2027 to 2030. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 39.48%; International Equity: 16.92%; Fixed-Income: 34.81%; Short-Term Fixed-Income: 4.40%; and Inflation-Protected Assets: 4.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund, and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	58.33%	U.S. Equity	39.86%	ŸLarge-Cap Growth Fund	7.83%
				ŸEnhanced Large-Cap Growth Index Fund	7.55%
				ŸLarge-Cap Value Fund	7.27%
				ŸEnhanced Large-Cap Value Index Fund	7.04%
				ŸGrowth & Income Fund	6.49%
				ŸSmall-Cap Equity Fund	3.15%
				ŸMid-Cap Growth Fund	0.29%
				ŸMid-Cap Value Fund	0.24%
		International Equity	18.47%	ŸInternational Equity Fund	5.22%
				ŸEnhanced International Equity Index Fund	4.60%
				ŸInternational Opportunities Fund	4.37%
				ŸEmerging Markets Equity Fund	3.38%
				ŸGlobal Natural Resources Fund	0.90%
FIXED-INCOME	41.67%	Fixed-Income	33.76%	ŸBond Fund	18.88%
				ŸBond Plus Fund	10.89%
				ŸHigh-Yield Fund	3.00%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	3.92%	ŸShort-Term Bond Fund	3.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	3.99%	ŸInflation-Linked Bond Fund	3.99%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2020 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.90%.

Best quarter: 13.85%, for the quarter ended June 30, 2009. Worst quarter: -14.95%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2020 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.52%	9.35%	5.41%		Oct. 15, 2004
Institutional Class		4.86%	9.64%	5.61%	[1]	Jan. 17, 2007
Premier Class		4.62%	9.46%	5.46%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.76%	8.11%	4.45%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.42%	7.15%	4.07%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2020 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.63%	9.57%	5.79%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2020 Fund Composite Index consisted of: 41.2% Russell 3000 Index; 33.6% Barclays U.S. Aggregate Bond Index; 17.6% MSCI All Country World Index ex USA; 3.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle Index Retirement Income Fund

TIAA-CREF Lifecycle Index Retirement Income Fund

Investment objective

The Lifecycle Index Retirement Income Fund seeks high total return over time primarily through income,

with a secondary emphasis on capital appreciation.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index Retirement Income Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index Retirement Income Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.50%	0.24%	0.24%
Acquired Fund Fees and Expenses	[2]	0.11%	0.11%	0.11%
Total Annual Fund Operating Expenses		0.76%	0.60%	0.45%
Waivers and Expense Reimbursements	[3],[4]	(0.39%)	(0.33%)	(0.33%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016 but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index Retirement Income Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	204	159	111
5 Years	384	302	219
10 Years	$ 906	$ 719	$ 535

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 35% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund invests in Underlying Funds according to a relatively stable asset allocation strategy that will not gradually adjust over time and is designed for investors who are already in or entering retirement (i.e., have already passed their retirement year). The Fund has a policy of investing at least 80% of its assets in Underlying Funds that are managed to seek investment returns that track particular market indices. For purposes of the 80% investment policy, the term “assets” means net assets, plus the amount of any borrowings for investment purposes.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 40.00% of the Fund’s assets to equity Underlying Funds and 60.00% of its assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations may be changed and actual allocations may vary up to ten percentage points from the targets. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which may change, are approximately as follows: U.S. Equity: 28.00%; International Equity: 12.00%; Fixed-Income: 40.00%; Short-Term Fixed-Income: 10.00%; and Inflation-Protected Assets: 10.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income) and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change. Investors should note that the Fund has a significant level of equity exposure and this exposure could cause fluctuation in the value of the Fund depending on the performance of the equity markets generally.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	39.92%	U.S. Equity	28.16%	ŸEquity Index Fund	28.16%
		International Equity	11.76%	ŸInternational Equity Index Fund	9.04%
				ŸEmerging Markets Equity Index Fund	2.72%
FIXED-INCOME	60.08%	Fixed-Income	50.02%	ŸBond Index Fund	50.02%
		Inflation-Protected Assets	10.06%	ŸInflation-Linked Bond Fund	10.06%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index Retirement Income Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.16%.

Best quarter: 6.74%, for the quarter ended September 30, 2010. Worst quarter: -4.69%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index Retirement Income Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		5.84%	7.43%	7.47%		Sep. 30, 2009
Institutional Class		6.15%	7.69%	7.74%		Sep. 30, 2009
Premier Class		5.99%	7.54%	7.59%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.01%	6.71%	6.75%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.46%	5.60%	5.65%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Lifecycle Index Retirement Income Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.34%	7.88%	7.95%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.09%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.26% of average daily net assets for Retirement Class shares; (ii) 0.16% of average daily net assets for Premier Class shares; and (iii) 0.01% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index Retirement Income Fund Composite Index consisted of: 50.0% Barclays U.S. Aggregate Bond Index; 28.0% Russell 3000 Index; 12.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2010 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2010 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle 2010 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 20% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

20.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have recently retired or have an approximate target retirement year within a few years, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors who retired in 2010 or plan to retire within a few years of 2010.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 45.00% of the Fund’s assets to equity Underlying Funds and 55.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative. The Fund had target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2010 and will reach the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2017 to 2020. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 30.80%; International Equity: 13.20%; Fixed-Income: 39.20%; Short-Term Fixed-Income: 8.40%; and Inflation-Protected Assets: 8.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	45.35%	U.S. Equity	30.76%	ŸLarge-Cap Growth Fund	6.15%
				ŸEnhanced Large-Cap Growth Index Fund	5.81%
				ŸLarge-Cap Value Fund	5.62%
				ŸEnhanced Large-Cap Value Index Fund	5.41%
				ŸGrowth & Income Fund	5.05%
				ŸSmall-Cap Equity Fund	2.44%
				ŸMid-Cap Growth Fund	0.16%
				ŸMid-Cap Value Fund	0.12%
		International Equity	14.59%	ŸInternational Equity Fund	4.17%
				ŸEnhanced International Equity Index Fund	3.60%
				ŸInternational Opportunities Fund	3.37%
				ŸEmerging Markets Equity Fund	2.77%
				ŸGlobal Natural Resources Fund	0.68%
FIXED-INCOME	54.65%	Fixed-Income	38.72%	ŸBond Fund	23.84%
				ŸBond Plus Fund	10.91%
				ŸHigh-Yield Fund	2.98%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	7.92%	ŸShort-Term Bond Fund	7.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	8.01%	ŸInflation-Linked Bond Fund	8.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

As of the close of business on December 31, 2014, the Lifecycle 2010 Fund Composite Index consisted of: 38.9% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000® Index; 13.7% MSCI All Country World Index ex USA; 7.8% Barclays U.S. 1–3 Year Government/Credit Bond Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2010 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.26%.

Bar Chart Closing [Text Block]

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Best quarter: 10.87%, for the quarter ended June 30, 2009. Worst quarter: -11.04%, for the quarter ended December 31, 2008.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

2.26%

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

10.87%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(11.04%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2010 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Ten Years

rr_AverageAnnualReturnYear10

4.71%

TIAA-CREF Lifecycle 2010 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Ten Years

rr_AverageAnnualReturnYear10

7.94%

TIAA-CREF Lifecycle 2010 Fund | Lifecycle 2010 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

6.13%

^[1]

Five Years

rr_AverageAnnualReturnYear05

8.31%

^[1]

Ten Years

rr_AverageAnnualReturnYear10

5.57%

^[1]

TIAA-CREF Lifecycle 2010 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.27%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.79%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.17%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.62%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 63

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

235

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

422

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 962

Annual Return 2005

rr_AnnualReturn2005

4.23%

Annual Return 2006

rr_AnnualReturn2006

8.39%

Annual Return 2007

rr_AnnualReturn2007

9.20%

Annual Return 2008

rr_AnnualReturn2008

(23.57%)

Annual Return 2009

rr_AnnualReturn2009

19.36%

Annual Return 2010

rr_AnnualReturn2010

11.53%

Annual Return 2011

rr_AnnualReturn2011

1.48%

Annual Return 2012

rr_AnnualReturn2012

12.27%

Annual Return 2013

rr_AnnualReturn2013

11.78%

Annual Return 2014

rr_AnnualReturn2014

4.38%

One Year

rr_AverageAnnualReturnYear01

4.38%

Five Years

rr_AverageAnnualReturnYear05

8.19%

Ten Years

rr_AverageAnnualReturnYear10

5.25%

Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 15, 2004

TIAA-CREF Lifecycle 2010 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.91%

Five Years

rr_AverageAnnualReturnYear05

7.15%

Ten Years

rr_AverageAnnualReturnYear10

4.34%

TIAA-CREF Lifecycle 2010 Fund | Retirement Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.94%

Five Years

rr_AverageAnnualReturnYear05

6.12%

Ten Years

rr_AverageAnnualReturnYear10

3.87%

TIAA-CREF Lifecycle 2010 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.64%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.52%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 53

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

193

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

345

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 787

One Year

rr_AverageAnnualReturnYear01

4.44%

Five Years

rr_AverageAnnualReturnYear05

8.30%

Ten Years

rr_AverageAnnualReturnYear10

5.30%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2010 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[2]

Other Expenses

rr_OtherExpensesOverAssets

0.02%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.37%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.49%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4],[5]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

145

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

262

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 604

One Year

rr_AverageAnnualReturnYear01

4.59%

Five Years

rr_AverageAnnualReturnYear05

8.46%

Ten Years

rr_AverageAnnualReturnYear10

5.46%

^[6]

Inception Date

rr_AverageAnnualReturnInceptionDate

Jan. 17, 2007

[1] As of the close of business on December 31, 2014, the Lifecycle 2010 Fund Composite Index consisted of: 38.9% Barclays U.S. Aggregate Bond Index; 31.8% Russell 3000 Index; 13.7% MSCI All Country World Index ex USA; 7.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 7.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[2] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[5] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[6] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

XML

TIAA-CREF Lifecycle Index 2055 Fund

TIAA-CREF Lifecycle Index 2055 Fund

Investment objective

The Lifecycle Index 2055 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2055 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2055 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.50%	0.24%	0.24%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		0.72%	0.56%	0.41%
Waivers and Expense Reimbursements	[3],[4]	(0.35%)	(0.29%)	(0.29%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2055 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	195	150	102
5 Years	366	284	201
10 Years	$ 862	$ 674	$ 489

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2055. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2055 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2062 to 2065. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.99%	U.S. Equity	63.21%	ŸEquity Index Fund	63.21%
		International Equity	26.78%	ŸInternational Equity Index Fund	20.58%
				ŸEmerging Markets Equity Index Fund	6.20%
FIXED-INCOME	10.01%	Fixed-Income	10.01%	ŸBond Index Fund	10.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2055 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.56%.

Best quarter: 11.36%, for the quarter ended March 31, 2012. Worst quarter: -3.64%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2055 Fund		One Year	Since Inception		Inception Date
Retirement Class		6.62%	9.33%		Apr. 29, 2011
Institutional Class		6.86%	9.60%		Apr. 29, 2011
Premier Class		6.73%	9.45%		Apr. 29, 2011
After Taxes on Distributions | Retirement Class		5.98%	8.81%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		4.08%	7.24%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	13.91%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	3.81%	[1]
Lifecycle Index 2055 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.18%	9.79%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2055 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI EAFE + Emerging Markets Index; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle 2015 Fund

TIAA-CREF Lifecycle 2015 Fund

Investment objective

The Lifecycle 2015 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2015 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2015 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.38%	0.38%	0.38%
Total Annual Fund Operating Expenses		0.80%	0.65%	0.50%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.63%	0.53%	0.38%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2015 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 64	$ 54	$ 39
3 Years	238	196	148
5 Years	427	350	268
10 Years	$ 974	$ 799	$ 617

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 16% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2015.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 50.00% of the Fund’s assets to equity Underlying Funds and 50.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2015 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2022 to 2025. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 34.30%; International Equity: 14.70%; Fixed-Income:38.20%; Short-Term Fixed-Income: 6.40%; and Inflation-Protected Assets: 6.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	50.36%	U.S. Equity	34.29%	ŸLarge-Cap Growth Fund	6.77%
				ŸEnhanced Large-Cap Growth Index Fund	6.49%
				ŸLarge-Cap Value Fund	6.26%
				ŸEnhanced Large-Cap Value Index Fund	6.05%
				ŸGrowth & Income Fund	5.63%
				ŸSmall-Cap Equity Fund	2.71%
				ŸMid-Cap Growth Fund	0.21%
				ŸMid-Cap Value Fund	0.17%
		International Equity	16.07%	ŸInternational Equity Fund	4.56%
				ŸEnhanced International Equity Index Fund	3.99%
				ŸInternational Opportunities Fund	3.75%
				ŸEmerging Markets Equity Fund	3.02%
				ŸGlobal Natural Resources Fund	0.75%
FIXED-INCOME	49.64%	Fixed-Income	37.72%	ŸBond Fund	22.87%
				ŸBond Plus Fund	10.89%
				ŸHigh-Yield Fund	2.97%
				ŸEmerging Markets Debt Fund	0.99%
		Short-Term Fixed-Income	5.92%	ŸShort-Term Bond Fund	5.91%
				ŸMoney Market Fund	0.01%
		Inflation-Protected Assets	6.00%	ŸInflation-Linked Bond Fund	6.00%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2015 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.57%.

Best quarter: 12.39%, for the quarter ended June 30, 2009. Worst quarter: -12.97%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2015 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.45%	8.71%	5.32%		Oct. 15, 2004
Institutional Class		4.78%	8.99%	5.54%	[1]	Jan. 17, 2007
Premier Class		4.63%	8.82%	5.38%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.56%	7.37%	4.29%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.45%	6.61%	3.98%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2015 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.36%	8.88%	5.70%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2015 Fund Composite Index consisted of: 37.6% Barclays U.S. Aggregate Bond Index; 35.6% Russell 3000 Index; 15.2% MSCI All Country World Index ex USA; 5.8% Barclays U.S. 1-3 Year Government/Credit Bond Index; and 5.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2045 Fund

Risk/Return:

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Risk/Return [Heading]

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TIAA-CREF Lifecycle 2045 Fund

Objective [Heading]

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Investment objective

Objective, Primary [Text Block]

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The Lifecycle 2045 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

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Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

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ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

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Portfolio turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 8% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

8.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal investment strategies

Strategy Narrative [Text Block]

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The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2045.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2045 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2052 to 2055. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.03%	U.S. Equity	62.11%	ŸLarge-Cap Growth Fund	12.12%
				ŸEnhanced Large-Cap Growth Index Fund	11.79%
				ŸLarge-Cap Value Fund	11.22%
				ŸEnhanced Large-Cap Value Index Fund	10.95%
				ŸGrowth & Income Fund	9.97%
				ŸSmall-Cap Equity Fund	4.91%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.92%	ŸInternational Equity Fund	7.81%
				ŸEnhanced International Equity Index Fund	7.14%
				ŸInternational Opportunities Fund	6.66%
				ŸEmerging Markets Equity Fund	4.97%
				ŸGlobal Natural Resources Fund	1.34%
FIXED-INCOME	9.97%	Fixed-Income	9.96%	ŸHigh-Yield Fund	4.97%
				ŸBond Plus Fund	4.01%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifecycle 2045 Fund Composite Index consisted of: 63.0% Russell 3000® Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2045 Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.19%.

Bar Chart Closing [Text Block]

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Best quarter: 17.33%, for the quarter ended June 30, 2009. Worst quarter: -21.15%, for the quarter ended December 31, 2008.

Year to Date Return, Label

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The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

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Jun. 30, 2015

Bar Chart, Year to Date Return

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4.19%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

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Jun. 30, 2009

Highest Quarterly Return

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17.33%

Lowest Quarterly Return, Label

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Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Dec. 31, 2008

Lowest Quarterly Return

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(21.15%)

Index No Deduction for Fees, Expenses, Taxes [Text]

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(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

Performance Table Closing [Text Block]

rr_PerformanceTableClosingTextBlock

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

rr_AverageAnnualReturnCaption

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifecycle 2045 Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

12.56%

Five Years

rr_AverageAnnualReturnYear05

15.63%

Since Inception

rr_AverageAnnualReturnSinceInception

7.35%

^[1]

TIAA-CREF Lifecycle 2045 Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Five Years

rr_AverageAnnualReturnYear05

4.45%

Since Inception

rr_AverageAnnualReturnSinceInception

4.76%

^[1]

TIAA-CREF Lifecycle 2045 Fund | Lifecycle 2045 Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.30%

^[2]

Five Years

rr_AverageAnnualReturnYear05

11.85%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

5.15%

^[1],[2]

TIAA-CREF Lifecycle 2045 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.28%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.87%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.69%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 70

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

260

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

465

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,056

Annual Return 2008

rr_AnnualReturn2008

(38.92%)

Annual Return 2009

rr_AnnualReturn2009

28.28%

Annual Return 2010

rr_AnnualReturn2010

15.10%

Annual Return 2011

rr_AnnualReturn2011

(3.88%)

Annual Return 2012

rr_AnnualReturn2012

17.26%

Annual Return 2013

rr_AnnualReturn2013

25.98%

Annual Return 2014

rr_AnnualReturn2014

4.28%

One Year

rr_AverageAnnualReturnYear01

4.28%

Five Years

rr_AverageAnnualReturnYear05

11.25%

Since Inception

rr_AverageAnnualReturnSinceInception

4.14%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

TIAA-CREF Lifecycle 2045 Fund | Retirement Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

2.80%

Five Years

rr_AverageAnnualReturnYear05

10.34%

Since Inception

rr_AverageAnnualReturnSinceInception

3.31%

TIAA-CREF Lifecycle 2045 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.72%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.59%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 60

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

217

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

388

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 882

One Year

rr_AverageAnnualReturnYear01

4.48%

Five Years

rr_AverageAnnualReturnYear05

11.38%

Since Inception

rr_AverageAnnualReturnSinceInception

4.24%

^[7]

Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 30, 2009

TIAA-CREF Lifecycle 2045 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[3]

Other Expenses

rr_OtherExpensesOverAssets

0.03%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.44%

^[4]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.57%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.13%)

^[5],[6]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.44%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 45

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

170

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

305

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 701

One Year

rr_AverageAnnualReturnYear01

4.61%

Five Years

rr_AverageAnnualReturnYear05

11.54%

Since Inception

rr_AverageAnnualReturnSinceInception

4.41%

Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 30, 2007

TIAA-CREF Lifecycle 2045 Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.09%

Five Years

rr_AverageAnnualReturnYear05

8.75%

Since Inception

rr_AverageAnnualReturnSinceInception

3.02%

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2045 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[5] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[6] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[7] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

XML

TIAA-CREF Lifecycle Index 2060 Fund

TIAA-CREF Lifecycle Index 2060 Fund

Investment objective

The Lifecycle Index 2060 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2060 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2060 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		1.97%	1.72%	1.55%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		2.19%	2.04%	1.72%
Waivers and Expense Reimbursements	[3],[4]	(1.82%)	(1.77%)	(1.60%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2060 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	509	468	385
5 Years	1,007	934	783
10 Years	$ 2,380	$ 2,227	$ 1,896

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal period between September 26, 2014 (inception date) and May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2060. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2060 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2067 to 2070. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s target asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, for June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.94%	U.S. Equity	63.30%	ŸEquity Index Fund	63.30%
		International Equity	26.64%	ŸInternational Equity Index Fund	20.48%
				ŸEmerging Markets Equity Index Fund	6.16%
FIXED-INCOME	10.06%	Fixed-Income	10.06%	ŸBond Index Fund	10.06%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle 2040 Fund

TIAA-CREF Lifecycle 2040 Fund

Investment objective

The Lifecycle 2040 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2040 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2040 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.27%	0.02%	0.02%
Acquired Fund Fees and Expenses	[2]	0.44%	0.44%	0.44%
Total Annual Fund Operating Expenses		0.86%	0.71%	0.56%
Waivers and Expense Reimbursements	[3],[4]	(0.17%)	(0.12%)	(0.12%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.69%	0.59%	0.44%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2040 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 70	$ 60	$ 45
3 Years	257	215	167
5 Years	460	383	301
10 Years	$ 1,045	$ 871	$ 690

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 11% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2040.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2040 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2047 to 2050. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 61.88%; International Equity: 26.52%; Fixed-Income: 11.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.05%	U.S. Equity	62.18%	ŸLarge-Cap Growth Fund	12.15%
				ŸEnhanced Large-Cap Growth Index Fund	11.79%
				ŸLarge-Cap Value Fund	11.23%
				ŸEnhanced Large-Cap Value Index Fund	10.98%
				ŸGrowth & Income Fund	9.98%
				ŸSmall-Cap Equity Fund	4.91%
				ŸMid-Cap Growth Fund	0.61%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.87%	ŸInternational Equity Fund	7.79%
				ŸEnhanced International Equity Index Fund	7.08%
				ŸInternational Opportunities Fund	6.71%
				ŸEmerging Markets Equity Fund	4.94%
				ŸGlobal Natural Resources Fund	1.35%
FIXED-INCOME	9.95%	Fixed-Income	9.94%	ŸHigh-Yield Fund	4.98%
				ŸBond Plus Fund	3.98%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year for the last ten years. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2040 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.21%.

Best quarter: 17.54%, for the quarter ended June 30, 2009. Worst quarter: -20.27%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2040 Fund		One Year	Five Years	Ten Years		Inception Date
Retirement Class		4.38%	11.30%	5.94%		Oct. 15, 2004
Institutional Class		4.63%	11.58%	6.16%	[1]	Jan. 17, 2007
Premier Class		4.49%	11.42%	6.01%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.63%	10.14%	5.08%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.47%	8.83%	4.59%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.94%
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.71%
Lifecycle 2040 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.30%	11.85%	6.50%

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Institutional Class and Premier Class that is prior to their inception dates is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Institutional Class and Premier Class.

[2] As of the close of business on December 31, 2014, the Lifecycle 2040 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifestyle Moderate Fund

TIAA-CREF Lifestyle Moderate Fund

Investment objective

The Fund seeks long-term total return, consisting of capital appreciation and current income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifestyle Moderate Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none	none
Maximum Deferred Sales Charge	none	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none	none
Redemption or Exchange Fee	none	none	none	none
Account Maintenance Fee (annual fee on accounts under $2,000)	$ 15.00	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifestyle Moderate Fund		Retail Class	Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees		0.25%		0.15%
Other Expenses		0.15%	0.37%	0.13%	0.13%
Acquired Fund Fees and Expenses	[1]	0.40%	0.40%	0.40%	0.40%
Total Annual Fund Operating Expenses		0.90%	0.87%	0.78%	0.63%
Waivers and Expense Reimbursements	[2]	(0.12%)	(0.12%)	(0.13%)	(0.13%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.78%	0.75%	0.65%	0.50%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifestyle Moderate Fund - USD ($)	Retail Class	Retirement Class	Premier Class	Institutional Class
1 Year	$ 80	$ 77	$ 66	$ 51
3 Years	275	266	236	189
5 Years	487	470	420	338
10 Years	$ 1,097	$ 1,061	$ 954	$ 774

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 13% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term total return, consisting of capital appreciation and current income, through a relatively stable asset allocation strategy targeting a moderate risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 60% of the Fund’s assets in equity Underlying Funds and (2) approximately 40% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	60.15%	U.S. Equity	41.21%	ŸLarge-Cap Growth Fund	10.83%
				ŸLarge-Cap Value Fund	10.04%
				ŸGrowth & Income Fund	8.91%
				ŸEnhanced Large-Cap Growth Index Fund	3.76%
				ŸEnhanced Large-Cap Value Index Fund	3.47%
				ŸSmall-Cap Equity Fund	3.25%
				ŸMid-Cap Growth Fund	0.51%
				ŸMid-Cap Value Fund	0.44%
		International Equity	18.94%	ŸInternational Equity Fund	6.31%
				ŸInternational Opportunities Fund	4.45%
				ŸEnhanced International Equity Index Fund	3.81%
				ŸEmerging Markets Equity Fund	3.47%
				ŸGlobal Natural Resources Fund	0.90%
FIXED-INCOME	39.85%	Fixed-Income	39.85%	ŸBond Plus Fund	38.83%
				ŸHigh-Yield Fund	1.02%
		Short-Term Fixed-Income	0.00%	ŸMoney Market Fund	0.00%

Total 100.00% 100.00% 100.00%

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Moderate Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 3.23%.

Best quarter: 9.36%, for the quarter ended March 31, 2012. Worst quarter: -2.27%, for the quarter ended June 30, 2012.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifestyle Moderate Fund		One Year	Since Inception		Inception Date
Institutional Class		4.98%	11.86%		Dec. 09, 2011
Retail Class		4.63%	11.50%		Dec. 09, 2011
Retirement Class		4.74%	11.57%		Dec. 09, 2011
Premier Class		4.92%	11.69%		Dec. 09, 2011
After Taxes on Distributions | Institutional Class		3.54%	10.62%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.24%	8.87%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	20.13%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	2.86%	[1]
Lifestyle Moderate Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.92%	11.03%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[2] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Moderate Fund Composite Index consisted of: 42.0% Russell 3000 Index; 40.0% Barclays U.S. Aggregate Bond Index; and 18.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle Index 2020 Fund

TIAA-CREF Lifecycle Index 2020 Fund

Investment objective

The Lifecycle Index 2020 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2020 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2020 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.09%	0.09%	0.09%
Total Annual Fund Operating Expenses		0.52%	0.37%	0.22%
Waivers and Expense Reimbursements	[3],[4]	(0.15%)	(0.10%)	(0.10%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2020 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	152	109	61
5 Years	276	198	114
10 Years	$ 638	$ 458	$ 270

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 9% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2020. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 58.00% of the Fund’s assets to equity Underlying Funds and 42.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2020 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2027 to 2030. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 39.48%; International Equity: 16.92%; Fixed-Income: 34.80%; Short-Term Fixed-Income: 4.40%; and Inflation-Protected Assets: 4.40%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	58.09%	U.S. Equity	40.90%	ŸEquity Index Fund	40.90%
		International Equity	17.19%	ŸInternational Equity Index Fund	13.21%
				ŸEmerging Markets Equity Index Fund	3.98%
FIXED-INCOME	41.91%	Fixed-Income	37.93%	ŸBond Index Fund	37.93%
		Inflation-Protected Assets	3.98%	ŸInflation-Linked Bond Fund	3.98%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2020 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 1.65%.

Best quarter: 9.39%, for the quarter ended September 30, 2010. Worst quarter: -9.69%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2020 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.27%	9.19%	9.39%		Sep. 30, 2009
Institutional Class		6.48%	9.46%	9.65%		Sep. 30, 2009
Premier Class		6.36%	9.28%	9.48%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.57%	8.65%	8.86%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		3.77%	7.15%	7.33%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2020 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	6.73%	9.63%	9.86%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.07%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.28% of average daily net assets for Retirement Class shares; (ii) 0.18% of average daily net assets for Premier Class shares; and (iii) 0.03% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2020 Fund Composite Index consisted of: 41.2% Russell 3000 Index; 37.4% Barclays U.S. Aggregate Bond Index; 17.6% MSCI EAFE + Emerging Markets Index; and 3.8% Barclays U.S. Treasury Inflation Protected Securities Index (Series-L). The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

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TIAA-CREF Lifecycle 2045 Fund

TIAA-CREF Lifecycle 2045 Fund

Investment objective

The Lifecycle 2045 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle 2045 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle 2045 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.44%	0.44%	0.44%
Total Annual Fund Operating Expenses		0.87%	0.72%	0.57%
Waivers and Expense Reimbursements	[3],[4]	(0.18%)	(0.13%)	(0.13%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.69%	0.59%	0.44%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle 2045 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 70	$ 60	$ 45
3 Years	260	217	170
5 Years	465	388	305
10 Years	$ 1,056	$ 882	$ 701

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 8% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2045.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2045 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2052 to 2055. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Growth & Income Fund, Large-Cap Growth Fund, Large-Cap Value Fund, Mid-Cap Growth Fund, Mid-Cap Value Fund, Small-Cap Equity Fund, Enhanced Large-Cap Growth Index Fund and Enhanced Large-Cap Value Index Fund (U.S. Equity); International Equity Fund, International Opportunities Fund, Enhanced International Equity Index Fund, Global Natural Resources Fund and Emerging Markets Equity Fund (International Equity); Bond Fund, Bond Plus Fund, High-Yield Fund and Emerging Markets Debt Fund (Fixed-Income); Short-Term Bond Fund and Money Market Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders, and the portfolio management team may use tactical allocation to take advantage of short to intermediate term opportunities through a combination of positions in Underlying Funds. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	90.03%	U.S. Equity	62.11%	ŸLarge-Cap Growth Fund	12.12%
				ŸEnhanced Large-Cap Growth Index Fund	11.79%
				ŸLarge-Cap Value Fund	11.22%
				ŸEnhanced Large-Cap Value Index Fund	10.95%
				ŸGrowth & Income Fund	9.97%
				ŸSmall-Cap Equity Fund	4.91%
				ŸMid-Cap Growth Fund	0.62%
				ŸMid-Cap Value Fund	0.53%
		International Equity	27.92%	ŸInternational Equity Fund	7.81%
				ŸEnhanced International Equity Index Fund	7.14%
				ŸInternational Opportunities Fund	6.66%
				ŸEmerging Markets Equity Fund	4.97%
				ŸGlobal Natural Resources Fund	1.34%
FIXED-INCOME	9.97%	Fixed-Income	9.96%	ŸHigh-Yield Fund	4.97%
				ŸBond Plus Fund	4.01%
				ŸEmerging Markets Debt Fund	0.98%
		Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the Fund. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle 2045 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.19%.

Best quarter: 17.33%, for the quarter ended June 30, 2009. Worst quarter: -21.15%, for the quarter ended December 31, 2008.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle 2045 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		4.28%	11.25%	4.14%		Nov. 30, 2007
Institutional Class		4.61%	11.54%	4.41%		Nov. 30, 2007
Premier Class		4.48%	11.38%	4.24%	[1]	Sep. 30, 2009
After Taxes on Distributions | Retirement Class		2.80%	10.34%	3.31%
After Taxes on Distributions and Sale of Fund Shares | Institutional Class		3.09%	8.75%	3.02%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	7.35%	[2]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.76%	[2]
Lifecycle 2045 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[3]	7.30%	11.85%	5.15%	[2]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive the Fund's Management Fees equal to, on an annual basis, 0.10%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.25% of average daily net assets for Retirement Class shares; (ii) 0.15% of average daily net assets for Premier Class shares; and (iii) 0.00% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] The performance shown for the Premier Class that is prior to its inception date is based on performance of the Fund's Retirement Class. The performance for these periods has not been restated to reflect the lower expenses of the Premier Class.

[2] Performance is calculated from the inception date of the Retirement Class.

[3] As of the close of business on December 31, 2014, the Lifecycle 2045 Fund Composite Index consisted of: 63.0% Russell 3000 Index; 27.0% MSCI All Country World Index ex USA; and 10.0% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2060 Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2060 Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Lifecycle Index 2060 Fund seeks high total return over time through a combination of capital appreciation and income.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal period between September 26, 2014 (inception date) and May 31, 2015, the Fund’s portfolio turnover rate was 6% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

6.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2060. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 90.00% of the Fund’s assets to equity Underlying Funds and 10.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2060 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2067 to 2070. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s target asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, for June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	89.94%	U.S. Equity	63.30%	ŸEquity Index Fund	63.30%
		International Equity	26.64%	ŸInternational Equity Index Fund	20.48%
				ŸEmerging Markets Equity Index Fund	6.16%
FIXED-INCOME	10.06%	Fixed-Income	10.06%	ŸBond Index Fund	10.06%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Risk [Heading]

rr_RiskHeading

Principal investment risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

rr_RiskLoseMoney

You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Past performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

Performance information is not available for the Fund because the Fund has less than one calendar year of performance.

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.tiaa-cref.org

TIAA-CREF Lifecycle Index 2060 Fund | Retirement Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.05%

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.97%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.19%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.82%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.37%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 38

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

509

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

1,007

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 2,380

TIAA-CREF Lifecycle Index 2060 Fund | Premier Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.72%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

2.04%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.77%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.27%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 28

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

468

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

934

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 2,227

TIAA-CREF Lifecycle Index 2060 Fund | Institutional Class

Risk/Return:

rr_RiskReturnAbstract

Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Maximum Account Fee

rr_MaximumAccountFeeOverAssets

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

^[1]

Other Expenses

rr_OtherExpensesOverAssets

1.55%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.07%

^[2]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.72%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(1.60%)

^[3],[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.12%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 12

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

385

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

783

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,896

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

XML

TIAA-CREF Lifecycle Index 2035 Fund

TIAA-CREF Lifecycle Index 2035 Fund

Investment objective

The Lifecycle Index 2035 Fund seeks high total return over time through a combination of capital appreciation and income.

Fees and expenses

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

SHAREHOLDER FEES (fees paid directly from your investment)

Shareholder Fees - TIAA-CREF Lifecycle Index 2035 Fund	Retirement Class	Premier Class	Institutional Class
Maximum Sales Charge Imposed on Purchases (percentage of offering price)	none	none	none
Maximum Deferred Sales Charge	none	none	none
Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions	none	none	none
Redemption or Exchange Fee	none	none	none
Maximum Account Fee	none	none	none

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Annual Fund Operating Expenses - TIAA-CREF Lifecycle Index 2035 Fund		Retirement Class	Premier Class	Institutional Class
Management Fees		0.10%	0.10%	0.10%
Distribution (Rule 12b-1) Fees	[1]	0.05%	0.15%
Other Expenses		0.28%	0.03%	0.03%
Acquired Fund Fees and Expenses	[2]	0.07%	0.07%	0.07%
Total Annual Fund Operating Expenses		0.50%	0.35%	0.20%
Waivers and Expense Reimbursements	[3],[4]	(0.13%)	(0.08%)	(0.08%)
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement		0.37%	0.27%	0.12%

Example

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Expense Example - TIAA-CREF Lifecycle Index 2035 Fund - USD ($)	Retirement Class	Premier Class	Institutional Class
1 Year	$ 38	$ 28	$ 12
3 Years	147	104	56
5 Years	267	188	105
10 Years	$ 616	$ 435	$ 247

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 5% of the average value of its portfolio.

Principal investment strategies

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). In general, the Fund is designed for investors who have an approximate target retirement year in mind, and the Fund’s investments are adjusted from more aggressive to more conservative over time as the target retirement year approaches and for approximately seven to ten years afterwards. The Fund invests in Underlying Funds according to an asset allocation strategy designed for investors retiring or planning to retire within a few years of 2035. The Fund has a policy of investing at least 80% of its assets (net assets, plus the amount of any borrowings for investment purposes) in Underlying Funds that are managed to seek investment returns that track particular market indices.

The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), expects to allocate approximately 82.00% of the Fund’s assets to equity Underlying Funds and 18.00% of the Fund’s assets to fixed-income Underlying Funds. These allocations represent targets for equity and fixed-income asset classes. Target allocations will change over time and actual allocations may vary up to ten percentage points from the targets. The target allocations along the investment glidepath, illustrated in the chart below, gradually become more conservative, moving to target allocations of approximately 50% equity/50% fixed-income in the Fund’s target retirement year of 2035 and reaching the Fund’s final target allocation of approximately 40% equity/60% fixed-income at some point from 2042 to 2045. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (U.S. equity, international equity, fixed-income, short-term fixed-income and inflation-protected assets) represented by various Underlying Funds. These market sector allocations may vary by up to 10% from the Fund’s target market sector allocations. The Fund’s current target market sector allocations for June 30, 2016, which will change over time, are approximately as follows: U.S. Equity: 56.28%; International Equity: 24.12%; Fixed-Income: 19.60%; Short-Term Fixed-Income: 0.00%; and Inflation-Protected Assets: 0.00%.

The Fund’s target market sector allocations to Underlying Funds may include the TIAA-CREF Equity Index Fund (U.S. Equity); International Equity Index Fund and Emerging Markets Equity Index Fund (International Equity); Bond Index Fund (Fixed-Income); Short-Term Bond Index Fund (Short-Term Fixed-Income); and Inflation-Linked Bond Fund (Inflation-Protected Assets).

Additional or replacement Underlying Funds for each market sector, as well as additional or replacement market sectors, may be included when making future allocations if Advisors believes that such Underlying Funds and/or market sectors are appropriate in light of the Fund’s desired levels of risk and potential return at the particular time. The Fund’s portfolio management team may also add a new market sector if it believes that will help to achieve the Fund’s investment objective. The relative allocations among Underlying Funds within a market sector may be changed at any time without notice to shareholders. If 10% or more of a Fund’s assets are expected to be invested in any Underlying Fund or market sectors not listed above, shareholders will receive prior notice of such change.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector, as of June 30, 2015, are listed in the chart below. These allocations will change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	82.03%	U.S. Equity	57.76%	ŸEquity Index Fund	57.76%
		International Equity	24.27%	ŸInternational Equity Index Fund	18.65%
				ŸEmerging Markets Equity Index Fund	5.62%
FIXED-INCOME	17.97%	Fixed-Income	17.97%	ŸBond Index Fund	17.97%

Total 100.00% 100.00% 100.00%

The following chart shows how the investment glidepath for the Fund is expected to gradually move the Fund’s target allocations over time between the different target market sector allocations. The actual market sector allocations of the Fund may differ from this chart. The Fund seeks to achieve its final target market sector allocations approximately seven to ten years following the target date.

TIAA-CREF Active Lifecycle Funds
Years to Target Date	U.S. Equity	International Equity	Fixed-Income	Short-term Fixed-Income	Inflation- Protected Assets
45	63.00	27.00	10.00	-	-
40	63.00	27.00	10.00	-	-
35	63.00	27.00	10.00	-	-
30	63.00	27.00	10.00	-	-
25	63.00	27.00	10.00	-	-
20	57.40	24.60	18.00	-	-
15	51.80	22.20	26.00	-	-
10	46.20	19.80	30.00	2.00	2.00
5	40.60	17.40	34.00	4.00	4.00
0	35.00	15.00	38.00	6.00	6.00
-5	31.50	13.50	39.00	8.00	8.00
-10	28.00	12.00	40.00	10.00	10.00
-15	28.00	12.00	40.00	10.00	10.00
-20	28.00	12.00	40.00	10.00	10.00
-25	28.00	12.00	40.00	10.00	10.00
-30	28.00	12.00	40.00	10.00	10.00

The Fund is designed to accommodate investors who invest in a fund up to their target retirement date, and plan to make gradual systematic withdrawals in retirement. In addition, investors should note that the Fund will continue to have a significant level of equity exposure up to, through and after its target retirement date, and this exposure could cause significant fluctuations in the value of the Fund depending on the performance of the equity markets generally.

Approximately seven to ten years after the Fund enters its target retirement year, the Board of Trustees may authorize the merger of the Fund into the Lifecycle Index Retirement Income Fund or other similar fund. Fund shareholders will receive prior notice of any such merger. The Lifecycle Index Retirement Income Fund is designed to maintain a relatively stable allocation among the Underlying Funds reflecting the resting point on the glidepath described in the chart above. More detailed information about the Lifecycle Index Retirement Income Fund is contained in the prospectus for that fund.

Principal investment risks

You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Index Risk—The risk that the Fund’s performance may not correspond to its benchmark index for any period of time and may underperform such index or the overall financial market. Additionally, to the extent that the Fund’s investments vary from the composition of its benchmark index, the Fund’s performance could potentially vary from the index’s performance to a greater extent than if the Fund merely attempted to replicate the index.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

· foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Past performance

The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Retirement Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Retirement Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Retirement Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Retirement, Institutional and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Retirement Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Retirement Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

ANNUAL TOTAL RETURNS FOR THE RETIREMENT CLASS SHARES (%)† Lifecycle Index 2035 Fund

^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 2.44%.

Best quarter: 11.89%, for the quarter ended September 30, 2010. Worst quarter: -14.45%, for the quarter ended September 30, 2011.

AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

Average Annual Returns - TIAA-CREF Lifecycle Index 2035 Fund		One Year	Five Years	Since Inception		Inception Date
Retirement Class		6.51%	11.03%	11.36%		Sep. 30, 2009
Institutional Class		6.80%	11.31%	11.65%		Sep. 30, 2009
Premier Class		6.68%	11.15%	11.48%		Sep. 30, 2009
After Taxes on Distributions | Retirement Class		5.87%	10.55%	10.89%
After Taxes on Distributions and Sale of Fund Shares | Retirement Class		4.00%	8.72%	9.03%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)		12.56%	15.63%	16.09%	[1]
Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)		5.97%	4.45%	4.27%	[1]
Lifecycle Index 2035 Fund Composite Index (reflects no deductions for fees, expenses or taxes)	[2]	7.11%	11.50%	11.85%	[1]

Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

[1] The Retirement Class of the Fund has adopted a Distribution (Rule 12b-1) Plan that compensates the Fund's distributor, Teachers Personal Investors Services, Inc. ("TPIS"), for its expenses in providing distribution, promotional and/or shareholder services to Retirement Class shares at the annual rate of 0.05% of average daily net assets attributable to Retirement Class shares. TPIS has contractually agreed not to seek payment of this fee under the Plan for Retirement Class shares through September 30, 2016, unless changed with approval of the Board of Trustees.

[2] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[3] Advisors has contractually agreed to waive a portion of the Fund's Management Fees equal to, on an annual basis, 0.05%. This waiver will remain in effect through September 30, 2016, unless changed with approval of the Board of Trustees.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc. ("Advisors"), has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.30% of average daily net assets for Retirement Class shares; (ii) 0.20% of average daily net assets for Premier Class shares; and (iii) 0.05% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.

[1] Performance is calculated from the inception date of the Retirement Class.

[2] As of the close of business on December 31, 2014, the Lifecycle Index 2035 Fund Composite Index consisted of: 58.0% Russell 3000 Index; 24.8% MSCI EAFE + Emerging Markets Index; and 17.2% Barclays U.S. Aggregate Bond Index. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Oct. 01, 2015

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Label

Element

Value

TIAA-CREF Lifestyle Aggressive Growth Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifestyle Aggressive Growth Fund

Objective [Heading]

rr_ObjectiveHeading

Investment objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The Fund seeks long-term growth of capital.

Expense [Heading]

rr_ExpenseHeading

Fees and expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund:

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

SHAREHOLDER FEES (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

Sep. 30, 2016

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the fiscal year ended May 31, 2015, the Fund’s portfolio turnover rate was 14% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

14.00%

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

"Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

Expense Example [Heading]

rr_ExpenseExampleHeading

Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

This example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses, before expense reimbursements, remain the same. The example assumes that the Fund’s fee waiver and/or expense reimbursement agreement will remain in place through September 30, 2016, but that there will be no waiver or expense reimbursement agreement in effect thereafter. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal investment strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

The Fund is a “fund of funds” that invests in Institutional Class shares of other funds of the Trust and potentially in other investment pools or investment products (collectively, the “Underlying Funds”). The Fund is designed for investors seeking long-term growth of capital through a relatively stable asset allocation strategy targeting an aggressive growth risk-return profile. The Fund’s investment adviser, Teachers Advisors, Inc. (“Advisors”), generally seeks to meet the Fund’s investment objective by investing: (1) approximately 100% of the Fund’s assets in equity Underlying Funds and (2) approximately 0% of the Fund’s assets in fixed-income Underlying Funds. The Fund may deviate from these target allocations by up to ten percentage points depending upon current market conditions and outlook.

The Underlying Funds’ allocation targets generally represent targets for investments in equity and fixed-income asset classes. Within the equity and fixed-income asset classes, Advisors allocates the Fund’s investments to particular market sectors (which may include U.S. equity, international equity, fixed-income and short-term fixed-income) represented by various Underlying Funds. To maintain an appropriate allocation among the Underlying Funds, the portfolio managers monitor the domestic and foreign equity markets, as well as overall financial and economic conditions. The Fund may sometimes be more heavily weighted toward equities or fixed-income than the target allocations, if the portfolio managers believe market conditions warrant. For example, the Fund may increase its holdings in fixed-income Underlying Funds in periods when the portfolio managers believe the equity markets will decline. The market sector allocations and Underlying Fund allocations may also be changed over time by the portfolio managers, including the addition and removal of market sectors and Underlying Funds in which the Fund invests in light of the Fund’s desired level of risk and potential return at a particular time as evaluated by the portfolio managers based on a mix of qualitative and quantitative factors. The portfolio managers may also opportunistically purchase other Funds or other investment pools or investment products, based on the portfolio managers’ evaluation of the market sectors and/or Underlying Funds without prior notice to shareholders.

As a result of its investments in the Underlying Funds, the Fund’s returns will reflect investments in a mix of domestic and foreign equities of companies of various sizes and a variety of domestic and foreign fixed-income instruments of private and governmental issuers of varying maturities and credit qualities.

As part of the Fund’s ability to invest in unaffiliated investment products or pools noted above, the Fund may invest in exchange-traded funds (“ETFs”) and exchange-traded notes (“ETNs”) to gain exposure to various market sectors or securities in order to effect its asset allocation strategy. Additionally, the Fund may use ETFs and ETNs for cash management, hedging or defensive purposes. ETFs and ETNs will be subject to the risks associated with the types of securities or sectors that they track, while ETNs, which are structured as fixed-income obligations, will also be subject to the general risks of fixed-income securities, including credit risk.

The Fund’s asset class allocations, market sector allocations within each asset class, and Underlying Fund allocations within each market sector as of June 30, 2015, are listed in the chart below. These allocations may change over time. Underlying Fund allocations in particular may change from year to year.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds	Allocation
EQUITY	99.99%	U.S. Equity	69.21%	ŸLarge-Cap Growth Fund	18.01%
				ŸLarge-Cap Value Fund	16.60%
				ŸGrowth & Income Fund	14.78%
				ŸEnhanced Large-Cap Growth Index Fund	6.41%
				ŸEnhanced Large-Cap Value Index Fund	5.96%
				ŸSmall-Cap Equity Fund	5.46%
				ŸMid-Cap Growth Fund	1.06%
				ŸMid-Cap Value Fund	0.93%
		International Equity	30.78%	ŸInternational Equity Fund	10.21%
				ŸInternational Opportunities Fund	7.38%
				ŸEnhanced International Equity Index Fund	6.31%
				ŸEmerging Markets Equity Fund	5.39%
				ŸGlobal Natural Resources Fund	1.49%
FIXED-INCOME	0.01%	Short-Term Fixed-Income	0.01%	ŸMoney Market Fund	0.01%

Total 100.00% 100.00% 100.00%

Risk [Heading]

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Principal investment risks

Risk Narrative [Text Block]

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You could lose money over short or long periods by investing in this Fund. An investment in the Fund, due to the nature of the Fund’s portfolio holdings, typically is subject to the following principal investment risks:

· Asset Allocation Risk—The risk that the Fund may not achieve its target allocations. In addition, there is the risk that the asset allocations may not achieve the desired risk-return characteristic or that the selection of Underlying Funds and the allocations among them will result in the Fund underperforming other similar funds or cause an investor to lose money.

· Underlying Funds Risks—The Fund is exposed to the risks of the Underlying Funds in which it invests in direct proportion to the amount of assets the Fund allocates to each Underlying Fund. Because the Fund targets its investments in a significantly higher percentage of equity Underlying Funds, Equity Underlying Fund Risks are expected to predominate.

· Equity Underlying Funds Risks—The risks of investing in equity Underlying Funds include risks specific to their investment strategies, as well as risks related to the equity markets in general, such as:

· market risk—The risk that the price of equity investments may decline in response to general market and economic conditions or events, including conditions and developments outside of the financial markets;

· issuer risk—The risk that an issuer’s earnings prospects and overall financial position will deteriorate, causing a decline in the value of the issuer’s financial instruments over short or extended periods of time; and

·foreign investment risk—The increased risks of adverse issuer, political, regulatory, currency, market or economic developments compared to investments in U.S. issuers, which can result in greater market and price volatility.

· Fixed-Income Underlying Funds Risks—The risks of investing in fixed-income Underlying Funds include risks specific to their investment strategies, as well as risks related to the fixed-income markets in general, such as:

· credit risk—The risk that a decline in an issuer’s financial position may prevent it from making principal and interest payments on fixed-income investments held by a Fund when due;

· interest rate risk—The risk that the value or yield of fixed-income investments may decline if interest rates change, which could adversely affect a Fund’s income or the value of its holdings;

· income volatility risk—The risk that the level of current income from a Fund’s portfolio of fixed-income securities may decline due to rapid and unpredictable changes in prevailing market interest rates;

· call risk—The risk that, during periods of falling interest rates, an issuer may call (or repay) a fixed-income security prior to maturity, resulting in a decline in a Fund’s income; and

· extension risk—The risk that during periods of rising interest rates, borrowers may pay off their mortgage loans later than expected, preventing a Fund from reinvesting principal proceeds at higher interest rates and resulting in less income than potentially available.

· Active Management Risk—The risk that the strategy, investment selection or trading execution of Advisors could cause the Fund or an Underlying Fund to underperform its benchmark index or mutual funds with similar investment objectives.

· Fund of Funds Risk—The ability of the Fund to achieve its investment objective will depend in part upon the ability of the Underlying Funds to achieve their investment objectives. There can be no guarantee that any Underlying Fund will achieve its investment objective.

There can be no assurances that the Fund will achieve its investment objective. You should not consider the Fund to be a complete investment program. Please see the non-summary portion of the Prospectus for more detailed information about the risks described above, including the risks of the Underlying Funds.

Risk Lose Money [Text]

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You could lose money over short or long periods by investing in this Fund.

Bar Chart and Performance Table [Heading]

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Past performance

Performance Narrative [Text Block]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year. The bar chart shows the annual total returns of the Institutional Class of the Fund, before taxes, in each full calendar year since inception of the class. Because the expenses vary across share classes, the performance of the Institutional Class may vary from the other share classes. Below the bar chart are the best and worst returns of the Institutional Class for a calendar quarter during the full calendar-year periods covered by the bar chart. The performance table following the bar chart shows the Fund’s average annual total returns for the Institutional, Retail, Retirement and Premier Classes over the one-year, five-year, ten-year and since-inception periods (where applicable) ended December 31, 2014, and how those returns compare to those of certain broad-based securities market indices and a composite index based on the Fund’s target allocations. After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

The returns shown below reflect previous agreements by Advisors to waive or reimburse the Fund and certain Underlying Funds for certain fees and expenses. Without these waivers and reimbursements, the returns of the Fund would have been lower. Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future. The indices listed below are unmanaged, and you cannot invest directly in an index. The returns for the indices reflect no deduction for fees, expenses or taxes.

For current performance information of each share class, including performance to the most recent month-end, please visit www.tiaa-cref.org.

Performance Information Illustrates Variability of Returns [Text]

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The following chart and table help illustrate some of the risks of investing in the Fund by showing changes in the Fund's performance from year to year.

Performance Additional Market Index [Text]

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As of the close of business on December 31, 2014, the Lifestyle Aggressive Growth Fund Composite Index consisted of: 70.0% Russell 3000® Index; and 30.0% MSCI All Country World Index ex USA. The Fund’s composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark’s performance may vary over time.

Performance Availability Website Address [Text]

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www.tiaa-cref.org

Performance Past Does Not Indicate Future [Text]

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Past performance of the Fund (before and after taxes) is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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ANNUAL TOTAL RETURNS FOR THE INSTITUTIONAL CLASS SHARES (%)† Lifestyle Aggressive Growth Fund

Bar Chart Footnotes [Text Block]

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^†The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was 4.79%.

Bar Chart Closing [Text Block]

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Best quarter: 14.33%, for the quarter ended March 31, 2012. Worst quarter: -5.47%, for the quarter ended June 30, 2012.

Year to Date Return, Label

rr_YearToDateReturnLabel

The year-to-date return as of the most recent calendar quarter, which ended on June 30, 2015, was

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Jun. 30, 2015

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

4.79%

Highest Quarterly Return, Label

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Best quarter:

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2012

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

14.33%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst quarter:

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Jun. 30, 2012

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(5.47%)

Index No Deduction for Fees, Expenses, Taxes [Text]

rr_IndexNoDeductionForFeesExpensesTaxes

(reflects no deductions for fees, expenses or taxes)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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After-tax performance is shown only for the Institutional Class shares, and after-tax returns for the other Classes of shares will vary from the after-tax returns presented for Institutional Class shares.

Performance Table Closing [Text Block]

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Current performance of the Fund’s shares may be higher or lower than that shown above.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates in effect during the periods shown and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown. The after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(a), 401(k) or 403(b) plans or Individual Retirement Accounts (IRAs). After-tax returns are shown for only one class, and after-tax returns for other classes will vary.

Caption

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AVERAGE ANNUAL TOTAL RETURNS For the Periods Ended December 31, 2014

TIAA-CREF Lifestyle Aggressive Growth Fund | Russell 3000® Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

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One Year

rr_AverageAnnualReturnYear01

12.56%

Since Inception

rr_AverageAnnualReturnSinceInception

20.13%

^[1]

TIAA-CREF Lifestyle Aggressive Growth Fund | Barclays U.S. Aggregate Bond Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

5.97%

Since Inception

rr_AverageAnnualReturnSinceInception

2.86%

^[1]

TIAA-CREF Lifestyle Aggressive Growth Fund | Lifestyle Aggressive Growth Fund Composite Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

7.42%

^[2]

Since Inception

rr_AverageAnnualReturnSinceInception

16.57%

^[1],[2]

TIAA-CREF Lifestyle Aggressive Growth Fund | Retail Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

$ 15.00

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other Expenses

rr_OtherExpensesOverAssets

0.31%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.45%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.11%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.24%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.87%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 89

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

329

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

588

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,330

One Year

rr_AverageAnnualReturnYear01

4.23%

Since Inception

rr_AverageAnnualReturnSinceInception

16.30%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Aggressive Growth Fund | Retirement Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.49%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.45%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.04%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.24%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.80%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 82

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

307

Expense Example, with Redemption, 5 Years

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551

Expense Example, with Redemption, 10 Years

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$ 1,249

One Year

rr_AverageAnnualReturnYear01

4.26%

Since Inception

rr_AverageAnnualReturnSinceInception

16.39%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Aggressive Growth Fund | Premier Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Distribution (Rule 12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

0.15%

Other Expenses

rr_OtherExpensesOverAssets

0.25%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.45%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.95%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.25%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.70%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 72

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

278

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

501

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 1,144

One Year

rr_AverageAnnualReturnYear01

4.37%

Since Inception

rr_AverageAnnualReturnSinceInception

16.51%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Aggressive Growth Fund | Institutional Class

Risk/Return:

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Maximum Sales Charge Imposed on Purchases (percentage of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum Deferred Sales Charge

rr_MaximumDeferredSalesChargeOverOfferingPrice

none

Maximum Sales Charge Imposed on Reinvested Dividends and Other Distributions

rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther

none

Redemption or Exchange Fee

rr_RedemptionFeeOverRedemption

none

Account Maintenance Fee (annual fee on accounts under $2,000)

rr_ShareholderFeeOther

none

Management Fees

rr_ManagementFeesOverAssets

0.10%

Other Expenses

rr_OtherExpensesOverAssets

0.25%

Acquired Fund Fees and Expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.45%

^[3]

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

0.80%

Waivers and Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.25%)

^[4]

Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement

rr_NetExpensesOverAssets

0.55%

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 56

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

230

Expense Example, with Redemption, 5 Years

rr_ExpenseExampleYear05

420

Expense Example, with Redemption, 10 Years

rr_ExpenseExampleYear10

$ 967

Annual Return 2012

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19.18%

Annual Return 2013

rr_AnnualReturn2013

29.87%

Annual Return 2014

rr_AnnualReturn2014

4.51%

One Year

rr_AverageAnnualReturnYear01

4.51%

Since Inception

rr_AverageAnnualReturnSinceInception

16.67%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 09, 2011

TIAA-CREF Lifestyle Aggressive Growth Fund | Institutional Class | After Taxes on Distributions

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.02%

Since Inception

rr_AverageAnnualReturnSinceInception

15.43%

TIAA-CREF Lifestyle Aggressive Growth Fund | Institutional Class | After Taxes on Distributions and Sale of Fund Shares

Risk/Return:

rr_RiskReturnAbstract

One Year

rr_AverageAnnualReturnYear01

3.33%

Since Inception

rr_AverageAnnualReturnSinceInception

12.91%

[1] Performance is calculated from the inception date of the Institutional Class.

[2] As of the close of business on December 31, 2014, the Lifestyle Aggressive Growth Fund Composite Index consisted of: 70.0% Russell 3000 Index; and 30.0% MSCI All Country World Index ex USA. The Fund's composite benchmark, the components that make up a composite benchmark and the method of calculating a composite benchmark's performance may vary over time.

[3] "Acquired Fund Fees and Expenses" are the Fund's proportionate amount of the expenses of any investment companies or pools in which it invests. These expenses are not paid directly by Fund shareholders. Instead, Fund shareholders bear these expenses indirectly because they reduce Fund performance. Because "Acquired Fund Fees and Expenses" are included in the chart above, the Fund's operating expenses here will not correlate with the expenses included in the Financial Highlights in this Prospectus and the Fund's annual report.

[4] Under the Fund's expense reimbursement arrangements, the Fund's investment adviser, Teachers Advisors, Inc., has contractually agreed to reimburse the Fund for any Total Annual Fund Operating Expenses (excluding interest, taxes, brokerage commissions or other transactional expenses, Acquired Fund Fees and Expenses and extraordinary expenses) that exceed: (i) 0.49% of average daily net assets for Retail Class shares; (ii) 0.35% of average daily net assets for Retirement Class shares; (iii) 0.25% of average daily net assets for Premier Class shares; and (iv) 0.10% of average daily net assets for Institutional Class shares of the Fund. These expense reimbursement arrangements will continue through at least September 30, 2016, unless changed with approval of the Board of Trustees.