497

Rule 497 Document

On behalf of the TIAA-CREF Lifecycle Funds, Lifecycle Index Funds, and the Managed Allocation Fund (the “Funds”), each a series of TIAA-CREF Funds, and pursuant to Rule 497(e) under the Securities Act of 1933, as amended, attached for filing are exhibits containing information in interactive data format. The interactive data files included as an exhibit to this filing relate to the prospectus supplements filed with the Securities and Exchange Commission on behalf of the Funds pursuant to Rule 497(e) on July 12, 2013 (Accession No. 0000930413-13-003809), which is incorporated by reference into this Rule 497 Document.

EXHIBIT LIST

101. INS XBRL Instance Document

101. SCH XBRL Taxonomy Extension Schema

101. DEF XBRL Taxonomy Extension Definition Linkbase

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TIAA-CREF Lifecycle 2040 Fund

Risk/Return:

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Supplement [Text Block]

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Lifecycle 2040 Fund

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 retiring or planning to retire within a few years of 2040.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.89%	U.S. Equity	63.55%	•	Enhanced Large-Cap Value Index Fund	12.20%
				•	Large-Cap Value Fund	12.07%
				•	Enhanced Large-Cap Growth Index Fund	11.30%
				•	Large-Cap Growth Fund	11.18%
				•	Growth & Income Fund	10.25%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.34%	•	International Equity Fund	8.86%
				•	Enhanced International Equity Index Fund	7.67%
				•	Emerging Markets Equity Fund	5.74%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.63%
FIXED-INCOME	10.11%	Fixed-Income	9.78%	•	High-Yield Fund	5.89%
				•	Bond Plus Fund	3.89%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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/Return [Heading]

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TIAA-CREF Lifecycle 2040 Fund

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TIAA-CREF Lifecycle 2010 Fund

TIAA-CREF Lifecycle 2010 Fund

Lifecycle 2010 Fund

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 expects to allocate approximately 46.00% of its assets to equity Underlying Funds and 54.00% of its 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 10% 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 32.20%; International Equity: 13.80%; Fixed-Income: 38.80%; Short-Term Fixed-Income: 7.60%; and Inflation-Protected Assets: 7.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	47.47%	U.S. Equity	33.11%	•	Enhanced Large-Cap Value Index Fund	6.34%
				•	Large-Cap Value Fund	6.29%
				•	Enhanced Large-Cap Growth Index Fund	5.87%
				•	Large-Cap Growth Fund	5.82%
				•	Growth & Income Fund	5.43%
				•	Small-Cap Equity Fund	2.65%
				•	Mid-Cap Value Fund	0.39%
				•	Mid-Cap Growth Fund	0.32%
		International Equity	14.36%	•	International Equity Fund	4.96%
				•	Enhanced International Equity Index Fund	3.85%
				•	Emerging Markets Equity Fund	3.28%
				•	Global Natural Resources Fund	1.41%
				•	International Opportunities Fund	0.86%
FIXED-INCOME	52.53%	Fixed-Income	38.09%	•	Bond Fund	34.39%
				•	High-Yield Fund	2.85%
				•	Bond Plus Fund	0.85%
		Short-Term Fixed-Income	9.61%	•	Short-Term Bond Fund	9.26%
				•	Money Market Fund	0.35%
		Inflation-Protected Assets	4.83%	•	Inflation-Linked Bond Fund	4.83%
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.

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TIAA-CREF Lifecycle 2025 Fund

TIAA-CREF Lifecycle 2025 Fund

Lifecycle 2025 Fund

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 retiring or planning to retire within a few years of 2025.

     The Fund expects to allocate approximately 67.60% of its assets to equity Underlying Funds and 32.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 47.32%; International Equity: 20.28%; Fixed-Income: 29.20%; Short-Term Fixed-Income: 1.60%; and Inflation-Protected Assets: 1.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	69.78%	U.S. Equity	49.12%	•	Enhanced Large-Cap Value Index Fund	9.43%
				•	Large-Cap Value Fund	9.33%
				•	Enhanced Large-Cap Growth Index Fund	8.73%
				•	Large-Cap Growth Fund	8.63%
				•	Growth & Income Fund	7.96%
				•	Small-Cap Equity Fund	3.89%
				•	Mid-Cap Value Fund	0.63%
				•	Mid-Cap Growth Fund	0.52%
		International Equity	20.66%	•	International Equity Fund	7.02%
				•	Enhanced International Equity Index Fund	5.85%
				•	Emerging Markets Equity Fund	4.57%
				•	Global Natural Resources Fund	1.96%
				•	International Opportunities Fund	1.26%
FIXED-INCOME	30.22%	Fixed-Income	27.66%	•	Bond Fund	17.53%
				•	High-Yield Fund	5.36%
				•	Bond Plus Fund	4.77%
		Short-Term Fixed-Income	1.47%	•	Short-Term Bond Fund	1.13%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	1.09%	•	Inflation-Linked Bond Fund	1.09%
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.

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TIAA-CREF Lifecycle Index Retirement Income Fund

TIAA-CREF Lifecycle Index Retirement Income Fund

Lifecycle Index Retirement Income Fund

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 expects to allocate approximately 40.00% of its 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 10% from the targets. Within the equity and fixed-income asset classes, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which may change, are approximately as follows: U.S. Equity: 28.00%; International Equity: 12.00%; Fixed-Income: 50.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	40.43%	U.S. Equity	30.65%	•	Equity Index Fund	30.65%
		International Equity	9.78%	•	International Equity Index Fund	7.39%
				•	Emerging Markets Equity Index Fund	2.39%
FIXED-INCOME	59.57%	Fixed-Income	49.77%	•	Bond Index Fund	49.77%
		Inflation-Protected Assets	9.80%	•	Inflation-Linked Bond Fund	9.80%
Total	100.00%		100.00%			100.00%

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TIAA-CREF Lifecycle 2045 Fund

TIAA-CREF Lifecycle 2045 Fund

Lifecycle 2045 Fund

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 retiring or planning to retire within a few years of 2045.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.88%	U.S. Equity	63.58%	•	Large-Cap Value Fund	12.15%
				•	Enhanced Large-Cap Value Index Fund	12.15%
				•	Large-Cap Growth Fund	11.28%
				•	Enhanced Large-Cap Growth Index Fund	11.25%
				•	Growth & Income Fund	10.20%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.30%	•	International Equity Fund	8.81%
				•	Enhanced International Equity Index Fund	7.67%
				•	Emerging Markets Equity Fund	5.74%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.12%	Fixed-Income	9.78%	•	High-Yield Fund	5.91%
				•	Bond Plus Fund	3.87%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
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.

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Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Oct. 01, 2012

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TIAA-CREF Lifecycle Index 2040 Fund

TIAA-CREF Lifecycle Index 2040 Fund

Lifecycle Index 2040 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.26%	U.S. Equity	68.61%	•	Equity Index Fund	68.61%
		International Equity	21.65%	•	International Equity Index Fund	16.38%
				•	Emerging Markets Equity Index Fund	5.27%
FIXED-INCOME	9.74%	Fixed-Income	9.74%	•	Bond Index Fund	9.74%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2010 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

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Lifecycle Index 2010 Fund

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 expects to allocate approximately 46.00% of its assets to equity Underlying Funds and 54.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 32.20%; International Equity: 13.80%; Fixed-Income: 46.40%; and Inflation-Protected Assets: 7.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	47.50%	U.S. Equity	35.99%	•	Equity Index Fund	35.99%
		International Equity	11.51%	•	International Equity Index Fund	8.71%
				•	Emerging Markets Equity Index Fund	2.80%
FIXED-INCOME	52.50%	Fixed-Income	45.50%	•	Bond Index Fund	45.50%
		Inflation-Protected Assets	7.00%	•	Inflation-Linked Bond Fund	7.00%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2010 Fund

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TIAA-CREF Lifecycle Index 2010 Fund

TIAA-CREF Lifecycle Index 2010 Fund

Lifecycle Index 2010 Fund

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 expects to allocate approximately 46.00% of its assets to equity Underlying Funds and 54.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 32.20%; International Equity: 13.80%; Fixed-Income: 46.40%; and Inflation-Protected Assets: 7.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	47.50%	U.S. Equity	35.99%	•	Equity Index Fund	35.99%
		International Equity	11.51%	•	International Equity Index Fund	8.71%
				•	Emerging Markets Equity Index Fund	2.80%
FIXED-INCOME	52.50%	Fixed-Income	45.50%	•	Bond Index Fund	45.50%
		Inflation-Protected Assets	7.00%	•	Inflation-Linked Bond Fund	7.00%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Managed Allocation Fund

TIAA-CREF Managed Allocation Fund

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% of its assets in equity Underlying Funds including up to 5% of its assets in real estate Underlying Funds; and (2) approximately 40% 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 10%. 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 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 affect 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 May 31, 2013, are listed in the chart below. These allocations may change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	60.40%	U.S. Equity	43.88%	•	Enhanced Large-Cap Value Index Fund	8.44%
				•	Large-Cap Value Fund	8.30%
				•	Enhanced Large-Cap Growth Index Fund	7.82%
				•	Large-Cap Growth Fund	7.66%
				•	Growth & Income Fund	7.16%
				•	Small-Cap Equity Fund	3.49%
				•	Mid-Cap Value Fund	0.55%
				•	Mid-Cap Growth Fund	0.46%
		International Equity	16.52%	•	International Equity Fund	6.15%
				•	Enhanced International Equity Index Fund	5.01%
				•	Emerging Markets Equity Fund	4.02%
				•	International Opportunities Fund	1.09%
				•	Global Natural Resources Fund	0.25%
FIXED-INCOME	39.60%	Fixed-Income	39.26%	•	Bond Plus Fund	37.25%
				•	High-Yield Fund	2.01%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
Total	100.00%		100.00%			100.00%

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TIAA-CREF Lifecycle Index 2030 Fund

TIAA-CREF Lifecycle Index 2030 Fund

Lifecycle Index 2030 Fund

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 expects to allocate approximately 75.60% of its assets to equity Underlying Funds and 24.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 52.92%; International Equity: 22.68%; Fixed-Income: 24.40%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	77.86%	U.S. Equity	59.17%	•	Equity Index Fund	59.17%
		International Equity	18.69%	•	International Equity Index Fund	14.13%
				•	Emerging Markets Equity Index Fund	4.56%
FIXED-INCOME	22.14%	Fixed-Income	22.14%	•	Bond Index Fund	22.14%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

XML

TIAA-CREF Lifecycle Index 2045 Fund

TIAA-CREF Lifecycle Index 2045 Fund

Lifecycle Index 2045 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.27%	U.S. Equity	68.63%	•	Equity Index Fund	68.63%
		International Equity	21.64%	•	International Equity Index Fund	16.36%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.73%	Fixed-Income	9.73%	•	Bond Index Fund	9.73%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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Label

Element

Value

TIAA-CREF Lifecycle Index 2020 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index 2020 Fund

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 expects to allocate approximately 59.60% of its assets to equity Underlying Funds and 40.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 41.72%; International Equity: 17.88%; Fixed-Income: 36.80%; and Inflation-Protected Assets: 3.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	61.77%	U.S. Equity	46.87%	•	Equity Index Fund	46.87%
		International Equity	14.90%	•	International Equity Index Fund	11.27%
				•	Emerging Markets Equity Index Fund	3.63%
FIXED-INCOME	38.23%	Fixed-Income	35.15%	•	Bond Index Fund	35.15%
		Inflation-Protected Assets	3.08%	•	Inflation-Linked Bond Fund	3.08%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2020 Fund

XML

Label

Element

Value

TIAA-CREF Lifecycle Index 2050 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index 2050 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.25%	U.S. Equity	68.59%	•	Equity Index Fund	68.59%
		International Equity	21.66%	•	International Equity Index Fund	16.38%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.75%	Fixed-Income	9.75%	•	Bond Index Fund	9.75%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2050 Fund

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Label

Element

Value

TIAA-CREF Lifecycle Index Retirement Income Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index Retirement Income Fund

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 expects to allocate approximately 40.00% of its 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 10% from the targets. Within the equity and fixed-income asset classes, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which may change, are approximately as follows: U.S. Equity: 28.00%; International Equity: 12.00%; Fixed-Income: 50.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	40.43%	U.S. Equity	30.65%	•	Equity Index Fund	30.65%
		International Equity	9.78%	•	International Equity Index Fund	7.39%
				•	Emerging Markets Equity Index Fund	2.39%
FIXED-INCOME	59.57%	Fixed-Income	49.77%	•	Bond Index Fund	49.77%
		Inflation-Protected Assets	9.80%	•	Inflation-Linked Bond Fund	9.80%
Total	100.00%		100.00%			100.00%

Risk/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index Retirement Income Fund

XML

TIAA-CREF Lifecycle 2015 Fund

TIAA-CREF Lifecycle 2015 Fund

Lifecycle 2015 Fund

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 retiring or planning to retire within a few years of 2015.

     The Fund expects to allocate approximately 51.60% of its assets to equity Underlying Funds and 48.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 36.12%; International Equity: 15.48%; Fixed-Income: 37.20%; Short-Term Fixed-Income: 5.60%; and Inflation-Protected Assets: 5.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	53.73%	U.S. Equity	37.61%	•	Large-Cap Value Fund	7.19%
				•	Enhanced Large-Cap Value Index Fund	7.18%
				•	Large-Cap Growth Fund	6.66%
				•	Enhanced Large-Cap Growth Index Fund	6.65%
				•	Growth & Income Fund	6.12%
				•	Small-Cap Equity Fund	2.99%
				•	Mid-Cap Value Fund	0.45%
				•	Mid-Cap Growth Fund	0.37%
		International Equity	16.12%	•	International Equity Fund	5.53%
				•	Enhanced International Equity Index Fund	4.41%
				•	Emerging Markets Equity Fund	3.64%
				•	Global Natural Resources Fund	1.56%
				•	International Opportunities Fund	0.98%
FIXED-INCOME	46.27%	Fixed-Income	35.81%	•	Bond Fund	30.98%
				•	High-Yield Fund	3.42%
				•	Bond Plus Fund	1.41%
		Short-Term Fixed-Income	5.48%	•	Short-Term Bond Fund	5.14%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	4.98%	•	Inflation-Linked Bond Fund	4.98%
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.

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TIAA-CREF Lifecycle 2020 Fund

TIAA-CREF Lifecycle 2020 Fund

Lifecycle 2020 Fund

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 retiring or planning to retire within a few years of 2020.

     The Fund expects to allocate approximately 59.60% of its assets to equity Underlying Funds and 40.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 41.72%; International Equity: 17.88%; Fixed-Income: 33.20%; Short-Term Fixed-Income: 3.60%; and Inflation-Protected Assets: 3.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	61.75%	U.S. Equity	43.34%	•	Enhanced Large-Cap Value Index Fund	8.31%
				•	Large-Cap Value Fund	8.23%
				•	Enhanced Large-Cap Growth Index Fund	7.70%
				•	Large-Cap Growth Fund	7.62%
				•	Growth & Income Fund	7.05%
				•	Small-Cap Equity Fund	3.44%
				•	Mid-Cap Value Fund	0.54%
				•	Mid-Cap Growth Fund	0.45%
		International Equity	18.41%	•	International Equity Fund	6.28%
				•	Enhanced International Equity Index Fund	5.14%
				•	Emerging Markets Equity Fund	4.11%
				•	Global Natural Resources Fund	1.76%
				•	International Opportunities Fund	1.12%
FIXED-INCOME	38.25%	Fixed-Income	31.75%	•	Bond Fund	24.54%
				•	High-Yield Fund	4.39%
				•	Bond Plus Fund	2.82%
		Short-Term Fixed-Income	3.47%	•	Short-Term Bond Fund	3.13%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	3.03%	•	Inflation-Linked Bond Fund	3.03%
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 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.

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TIAA-CREF Lifecycle 2025 Fund

Risk/Return:

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Supplement [Text Block]

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Lifecycle 2025 Fund

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 retiring or planning to retire within a few years of 2025.

     The Fund expects to allocate approximately 67.60% of its assets to equity Underlying Funds and 32.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 47.32%; International Equity: 20.28%; Fixed-Income: 29.20%; Short-Term Fixed-Income: 1.60%; and Inflation-Protected Assets: 1.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	69.78%	U.S. Equity	49.12%	•	Enhanced Large-Cap Value Index Fund	9.43%
				•	Large-Cap Value Fund	9.33%
				•	Enhanced Large-Cap Growth Index Fund	8.73%
				•	Large-Cap Growth Fund	8.63%
				•	Growth & Income Fund	7.96%
				•	Small-Cap Equity Fund	3.89%
				•	Mid-Cap Value Fund	0.63%
				•	Mid-Cap Growth Fund	0.52%
		International Equity	20.66%	•	International Equity Fund	7.02%
				•	Enhanced International Equity Index Fund	5.85%
				•	Emerging Markets Equity Fund	4.57%
				•	Global Natural Resources Fund	1.96%
				•	International Opportunities Fund	1.26%
FIXED-INCOME	30.22%	Fixed-Income	27.66%	•	Bond Fund	17.53%
				•	High-Yield Fund	5.36%
				•	Bond Plus Fund	4.77%
		Short-Term Fixed-Income	1.47%	•	Short-Term Bond Fund	1.13%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	1.09%	•	Inflation-Linked Bond Fund	1.09%
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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2025 Fund

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TIAA-CREF Lifecycle 2020 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle 2020 Fund

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 retiring or planning to retire within a few years of 2020.

     The Fund expects to allocate approximately 59.60% of its assets to equity Underlying Funds and 40.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 41.72%; International Equity: 17.88%; Fixed-Income: 33.20%; Short-Term Fixed-Income: 3.60%; and Inflation-Protected Assets: 3.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	61.75%	U.S. Equity	43.34%	•	Enhanced Large-Cap Value Index Fund	8.31%
				•	Large-Cap Value Fund	8.23%
				•	Enhanced Large-Cap Growth Index Fund	7.70%
				•	Large-Cap Growth Fund	7.62%
				•	Growth & Income Fund	7.05%
				•	Small-Cap Equity Fund	3.44%
				•	Mid-Cap Value Fund	0.54%
				•	Mid-Cap Growth Fund	0.45%
		International Equity	18.41%	•	International Equity Fund	6.28%
				•	Enhanced International Equity Index Fund	5.14%
				•	Emerging Markets Equity Fund	4.11%
				•	Global Natural Resources Fund	1.76%
				•	International Opportunities Fund	1.12%
FIXED-INCOME	38.25%	Fixed-Income	31.75%	•	Bond Fund	24.54%
				•	High-Yield Fund	4.39%
				•	Bond Plus Fund	2.82%
		Short-Term Fixed-Income	3.47%	•	Short-Term Bond Fund	3.13%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	3.03%	•	Inflation-Linked Bond Fund	3.03%
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 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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2020 Fund

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TIAA-CREF Lifecycle Index 2045 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index 2045 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.27%	U.S. Equity	68.63%	•	Equity Index Fund	68.63%
		International Equity	21.64%	•	International Equity Index Fund	16.36%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.73%	Fixed-Income	9.73%	•	Bond Index Fund	9.73%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2045 Fund

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TIAA-CREF Lifecycle Index 2015 Fund

TIAA-CREF Lifecycle Index 2015 Fund

Lifecycle Index 2015 Fund

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 expects to allocate approximately 51.60% of its assets to equity Underlying Funds and 48.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 36.12%; International Equity: 15.48%; Fixed-Income: 42.80%; and Inflation-Protected Assets: 5.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	53.75%	U.S. Equity	40.71%	•	Equity Index Fund	40.71%
		International Equity	13.04%	•	International Equity Index Fund	9.87%
				•	Emerging Markets Equity Index Fund	3.17%
FIXED-INCOME	46.25%	Fixed-Income	41.21%	•	Bond Index Fund	41.21%
		Inflation-Protected Assets	5.04%	•	Inflation-Linked Bond Fund	5.04%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2025 Fund

TIAA-CREF Lifecycle Index 2025 Fund

Lifecycle Index 2025 Fund

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 expects to allocate approximately 67.60% of its assets to equity Underlying Funds and 32.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 47.32%; International Equity: 20.28%; Fixed-Income: 30.80%; and Inflation-Protected Assets: 1.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	69.80%	U.S. Equity	53.00%	•	Equity Index Fund	53.00%
		International Equity	16.80%	•	International Equity Index Fund	12.70%
				•	Emerging Markets Equity Index Fund	4.10%
FIXED-INCOME	30.20%	Fixed-Income	29.08%	•	Bond Index Fund	29.08%
		Inflation-Protected Assets	1.12%	•	Inflation-Linked Bond Fund	1.12%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2035 Fund

Risk/Return:

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Lifecycle Index 2035 Fund

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 expects to allocate approximately 83.60% of its assets to equity Underlying Funds and 16.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 58.52%; International Equity: 25.08%; Fixed-Income: 16.40%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	85.81%	U.S. Equity	65.23%	•	Equity Index Fund	65.23%
		International Equity	20.58%	•	International Equity Index Fund	15.57%
				•	Emerging Markets Equity Index Fund	5.01%
FIXED-INCOME	14.19%	Fixed-Income	14.19%	•	Bond Index Fund	14.19%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

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TIAA-CREF Lifecycle Index 2035 Fund

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TIAA-CREF Lifecycle Index 2055 Fund

Risk/Return:

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Supplement [Text Block]

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Lifecycle Index 2055 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.25%	U.S. Equity	68.61%	•	Equity Index Fund	68.61%
		International Equity	21.64%	•	International Equity Index Fund	16.36%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.75%	Fixed-Income	9.75%	•	Bond Index Fund	9.75%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2055 Fund

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TIAA-CREF Lifecycle Retirement Income Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Retirement Income Fund

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 expects to allocate approximately 40.00% of its 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 10% from the targets. Within the equity and fixed-income asset classes, the Fund allocates its 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, 2014, 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 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	40.34%	U.S. Equity	28.12%	•	Large-Cap Value Fund	5.42%
				•	Enhanced Large-Cap Value Index Fund	5.34%
				•	Large-Cap Growth Fund	5.03%
				•	Enhanced Large-Cap Growth Index Fund	4.93%
				•	Growth & Income Fund	4.58%
				•	Small-Cap Equity Fund	2.26%
				•	Mid-Cap Value Fund	0.31%
				•	Mid-Cap Growth Fund	0.25%
		International Equity	12.22%	•	International Equity Fund	4.20%
				•	Enhanced International Equity Index Fund	3.19%
				•	Emerging Markets Equity Fund	2.86%
				•	Global Natural Resources Fund	1.23%
				•	International Opportunities Fund	0.74%
FIXED-INCOME	59.66%	Fixed-Income	39.58%	•	Bond Fund	36.59%
				•	High-Yield Fund	2.50%
				•	Bond Plus Fund	0.49%
		Short-Term Fixed-Income	15.35%	•	Short-Term Bond Fund	15.02%
				•	Money Market Fund	0.33%
		Inflation-Protected Assets	4.73%	•	Inflation-Linked Bond Fund	4.73%
Total	100.00%		100.00%			100.00%

Risk/Return [Heading]

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TIAA-CREF Lifecycle Retirement Income Fund

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TIAA-CREF Lifecycle 2035 Fund

TIAA-CREF Lifecycle 2035 Fund

Lifecycle 2035 Fund

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 retiring or planning to retire within a few years of 2035.

     The Fund expects to allocate approximately 83.60% of its assets to equity Underlying Funds and 16.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 58.52%; International Equity: 25.08%; Fixed-Income: 16.40%; 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	85.43%	U.S. Equity	60.34%	•	Enhanced Large-Cap Value Index Fund	11.57%
				•	Large-Cap Value Fund	11.47%
				•	Enhanced Large-Cap Growth Index Fund	10.73%
				•	Large-Cap Growth Fund	10.62%
				•	Growth & Income Fund	9.74%
				•	Small-Cap Equity Fund	4.75%
				•	Mid-Cap Value Fund	0.79%
				•	Mid-Cap Growth Fund	0.67%
		International Equity	25.09%	•	International Equity Fund	8.46%
				•	Enhanced International Equity Index Fund	7.27%
				•	Emerging Markets Equity Fund	5.48%
				•	Global Natural Resources Fund	2.33%
				•	International Opportunities Fund	1.55%
FIXED-INCOME	14.57%	Fixed-Income	14.24%	•	High-Yield Fund	5.90%
				•	Bond Plus Fund	5.86%
				•	Bond Fund	2.48%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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.

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TIAA-CREF Lifecycle 2010 Fund

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Lifecycle 2010 Fund

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 expects to allocate approximately 46.00% of its assets to equity Underlying Funds and 54.00% of its 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 10% 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 32.20%; International Equity: 13.80%; Fixed-Income: 38.80%; Short-Term Fixed-Income: 7.60%; and Inflation-Protected Assets: 7.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	47.47%	U.S. Equity	33.11%	•	Enhanced Large-Cap Value Index Fund	6.34%
				•	Large-Cap Value Fund	6.29%
				•	Enhanced Large-Cap Growth Index Fund	5.87%
				•	Large-Cap Growth Fund	5.82%
				•	Growth & Income Fund	5.43%
				•	Small-Cap Equity Fund	2.65%
				•	Mid-Cap Value Fund	0.39%
				•	Mid-Cap Growth Fund	0.32%
		International Equity	14.36%	•	International Equity Fund	4.96%
				•	Enhanced International Equity Index Fund	3.85%
				•	Emerging Markets Equity Fund	3.28%
				•	Global Natural Resources Fund	1.41%
				•	International Opportunities Fund	0.86%
FIXED-INCOME	52.53%	Fixed-Income	38.09%	•	Bond Fund	34.39%
				•	High-Yield Fund	2.85%
				•	Bond Plus Fund	0.85%
		Short-Term Fixed-Income	9.61%	•	Short-Term Bond Fund	9.26%
				•	Money Market Fund	0.35%
		Inflation-Protected Assets	4.83%	•	Inflation-Linked Bond Fund	4.83%
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.

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TIAA-CREF Lifecycle 2010 Fund

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TIAA-CREF Lifecycle Retirement Income Fund

TIAA-CREF Lifecycle Retirement Income Fund

Lifecycle Retirement Income Fund

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 expects to allocate approximately 40.00% of its 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 10% from the targets. Within the equity and fixed-income asset classes, the Fund allocates its 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, 2014, 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 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	40.34%	U.S. Equity	28.12%	•	Large-Cap Value Fund	5.42%
				•	Enhanced Large-Cap Value Index Fund	5.34%
				•	Large-Cap Growth Fund	5.03%
				•	Enhanced Large-Cap Growth Index Fund	4.93%
				•	Growth & Income Fund	4.58%
				•	Small-Cap Equity Fund	2.26%
				•	Mid-Cap Value Fund	0.31%
				•	Mid-Cap Growth Fund	0.25%
		International Equity	12.22%	•	International Equity Fund	4.20%
				•	Enhanced International Equity Index Fund	3.19%
				•	Emerging Markets Equity Fund	2.86%
				•	Global Natural Resources Fund	1.23%
				•	International Opportunities Fund	0.74%
FIXED-INCOME	59.66%	Fixed-Income	39.58%	•	Bond Fund	36.59%
				•	High-Yield Fund	2.50%
				•	Bond Plus Fund	0.49%
		Short-Term Fixed-Income	15.35%	•	Short-Term Bond Fund	15.02%
				•	Money Market Fund	0.33%
		Inflation-Protected Assets	4.73%	•	Inflation-Linked Bond Fund	4.73%
Total	100.00%		100.00%			100.00%

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TIAA-CREF Lifecycle Index 2015 Fund

Risk/Return:

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Lifecycle Index 2015 Fund

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 expects to allocate approximately 51.60% of its assets to equity Underlying Funds and 48.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 36.12%; International Equity: 15.48%; Fixed-Income: 42.80%; and Inflation-Protected Assets: 5.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	53.75%	U.S. Equity	40.71%	•	Equity Index Fund	40.71%
		International Equity	13.04%	•	International Equity Index Fund	9.87%
				•	Emerging Markets Equity Index Fund	3.17%
FIXED-INCOME	46.25%	Fixed-Income	41.21%	•	Bond Index Fund	41.21%
		Inflation-Protected Assets	5.04%	•	Inflation-Linked Bond Fund	5.04%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2015 Fund

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TIAA-CREF Lifecycle 2055 Fund

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Lifecycle 2055 Fund

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 retiring or planning to retire within a few years of 2055.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.80%	U.S. Equity	63.58%	•	Large-Cap Value Fund	12.23%
				•	Enhanced Large-Cap Value Index Fund	12.13%
				•	Large-Cap Growth Fund	11.34%
				•	Enhanced Large-Cap Growth Index Fund	11.20%
				•	Growth & Income Fund	10.13%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.22%	•	International Equity Fund	8.71%
				•	Enhanced International Equity Index Fund	7.68%
				•	Emerging Markets Equity Fund	5.76%
				•	Global Natural Resources Fund	2.43%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.20%	Fixed-Income	9.87%	•	High-Yield Fund	5.96%
				•	Bond Plus Fund	3.91%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2055 Fund

XML

TIAA-CREF Lifecycle Index 2055 Fund

TIAA-CREF Lifecycle Index 2055 Fund

Lifecycle Index 2055 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.25%	U.S. Equity	68.61%	•	Equity Index Fund	68.61%
		International Equity	21.64%	•	International Equity Index Fund	16.36%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.75%	Fixed-Income	9.75%	•	Bond Index Fund	9.75%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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Label

Element

Value

TIAA-CREF Lifecycle Index 2040 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index 2040 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.26%	U.S. Equity	68.61%	•	Equity Index Fund	68.61%
		International Equity	21.65%	•	International Equity Index Fund	16.38%
				•	Emerging Markets Equity Index Fund	5.27%
FIXED-INCOME	9.74%	Fixed-Income	9.74%	•	Bond Index Fund	9.74%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2040 Fund

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Label

Element

Value

TIAA-CREF Lifecycle Index 2030 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle Index 2030 Fund

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 expects to allocate approximately 75.60% of its assets to equity Underlying Funds and 24.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 52.92%; International Equity: 22.68%; Fixed-Income: 24.40%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	77.86%	U.S. Equity	59.17%	•	Equity Index Fund	59.17%
		International Equity	18.69%	•	International Equity Index Fund	14.13%
				•	Emerging Markets Equity Index Fund	4.56%
FIXED-INCOME	22.14%	Fixed-Income	22.14%	•	Bond Index Fund	22.14%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle Index 2030 Fund

XML

TIAA-CREF Lifecycle Index 2035 Fund

TIAA-CREF Lifecycle Index 2035 Fund

Lifecycle Index 2035 Fund

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 expects to allocate approximately 83.60% of its assets to equity Underlying Funds and 16.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 58.52%; International Equity: 25.08%; Fixed-Income: 16.40%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	85.81%	U.S. Equity	65.23%	•	Equity Index Fund	65.23%
		International Equity	20.58%	•	International Equity Index Fund	15.57%
				•	Emerging Markets Equity Index Fund	5.01%
FIXED-INCOME	14.19%	Fixed-Income	14.19%	•	Bond Index Fund	14.19%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

XML

Label

Element

Value

TIAA-CREF Lifecycle 2030 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle 2030 Fund

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 retiring or planning to retire within a few years of 2030.

     The Fund expects to allocate approximately 75.60% of its assets to equity Underlying Funds and 24.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 52.92%; International Equity: 22.68%; Fixed-Income: 24.40%; 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	77.58%	U.S. Equity	54.72%	•	Enhanced Large-Cap Value Index Fund	10.48%
				•	Large-Cap Value Fund	10.40%
				•	Enhanced Large-Cap Growth Index Fund	9.72%
				•	Large-Cap Growth Fund	9.64%
				•	Growth & Income Fund	8.85%
				•	Small-Cap Equity Fund	4.32%
				•	Mid-Cap Value Fund	0.71%
				•	Mid-Cap Growth Fund	0.60%
		International Equity	22.86%	•	International Equity Fund	7.74%
				•	Enhanced International Equity Index Fund	6.55%
				•	Emerging Markets Equity Fund	5.02%
				•	Global Natural Resources Fund	2.14%
				•	International Opportunities Fund	1.41%
FIXED-INCOME	22.42%	Fixed-Income	22.07%	•	Bond Fund	10.28%
				•	High-Yield Fund	5.91%
				•	Bond Plus Fund	5.88%
		Short-Term Fixed-Income	0.35%	•	Money Market Fund	0.35%
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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2030 Fund

XML

TIAA-CREF Lifecycle Index 2020 Fund

TIAA-CREF Lifecycle Index 2020 Fund

Lifecycle Index 2020 Fund

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 expects to allocate approximately 59.60% of its assets to equity Underlying Funds and 40.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 41.72%; International Equity: 17.88%; Fixed-Income: 36.80%; and Inflation-Protected Assets: 3.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	61.77%	U.S. Equity	46.87%	•	Equity Index Fund	46.87%
		International Equity	14.90%	•	International Equity Index Fund	11.27%
				•	Emerging Markets Equity Index Fund	3.63%
FIXED-INCOME	38.23%	Fixed-Income	35.15%	•	Bond Index Fund	35.15%
		Inflation-Protected Assets	3.08%	•	Inflation-Linked Bond Fund	3.08%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2050 Fund

TIAA-CREF Lifecycle Index 2050 Fund

Lifecycle Index 2050 Fund

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 expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 63.00%; International Equity: 27.00%; Fixed-Income: 10.00%; 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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	90.25%	U.S. Equity	68.59%	•	Equity Index Fund	68.59%
		International Equity	21.66%	•	International Equity Index Fund	16.38%
				•	Emerging Markets Equity Index Fund	5.28%
FIXED-INCOME	9.75%	Fixed-Income	9.75%	•	Bond Index Fund	9.75%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle 2040 Fund

TIAA-CREF Lifecycle 2040 Fund

Lifecycle 2040 Fund

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 retiring or planning to retire within a few years of 2040.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.89%	U.S. Equity	63.55%	•	Enhanced Large-Cap Value Index Fund	12.20%
				•	Large-Cap Value Fund	12.07%
				•	Enhanced Large-Cap Growth Index Fund	11.30%
				•	Large-Cap Growth Fund	11.18%
				•	Growth & Income Fund	10.25%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.34%	•	International Equity Fund	8.86%
				•	Enhanced International Equity Index Fund	7.67%
				•	Emerging Markets Equity Fund	5.74%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.63%
FIXED-INCOME	10.11%	Fixed-Income	9.78%	•	High-Yield Fund	5.89%
				•	Bond Plus Fund	3.89%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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.

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TIAA-CREF Lifecycle 2030 Fund

TIAA-CREF Lifecycle 2030 Fund

Lifecycle 2030 Fund

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 retiring or planning to retire within a few years of 2030.

     The Fund expects to allocate approximately 75.60% of its assets to equity Underlying Funds and 24.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 52.92%; International Equity: 22.68%; Fixed-Income: 24.40%; 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	77.58%	U.S. Equity	54.72%	•	Enhanced Large-Cap Value Index Fund	10.48%
				•	Large-Cap Value Fund	10.40%
				•	Enhanced Large-Cap Growth Index Fund	9.72%
				•	Large-Cap Growth Fund	9.64%
				•	Growth & Income Fund	8.85%
				•	Small-Cap Equity Fund	4.32%
				•	Mid-Cap Value Fund	0.71%
				•	Mid-Cap Growth Fund	0.60%
		International Equity	22.86%	•	International Equity Fund	7.74%
				•	Enhanced International Equity Index Fund	6.55%
				•	Emerging Markets Equity Fund	5.02%
				•	Global Natural Resources Fund	2.14%
				•	International Opportunities Fund	1.41%
FIXED-INCOME	22.42%	Fixed-Income	22.07%	•	Bond Fund	10.28%
				•	High-Yield Fund	5.91%
				•	Bond Plus Fund	5.88%
		Short-Term Fixed-Income	0.35%	•	Money Market Fund	0.35%
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.

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Label

Element

Value

TIAA-CREF Lifecycle 2015 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle 2015 Fund

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 retiring or planning to retire within a few years of 2015.

     The Fund expects to allocate approximately 51.60% of its assets to equity Underlying Funds and 48.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 36.12%; International Equity: 15.48%; Fixed-Income: 37.20%; Short-Term Fixed-Income: 5.60%; and Inflation-Protected Assets: 5.60%.

     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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	53.73%	U.S. Equity	37.61%	•	Large-Cap Value Fund	7.19%
				•	Enhanced Large-Cap Value Index Fund	7.18%
				•	Large-Cap Growth Fund	6.66%
				•	Enhanced Large-Cap Growth Index Fund	6.65%
				•	Growth & Income Fund	6.12%
				•	Small-Cap Equity Fund	2.99%
				•	Mid-Cap Value Fund	0.45%
				•	Mid-Cap Growth Fund	0.37%
		International Equity	16.12%	•	International Equity Fund	5.53%
				•	Enhanced International Equity Index Fund	4.41%
				•	Emerging Markets Equity Fund	3.64%
				•	Global Natural Resources Fund	1.56%
				•	International Opportunities Fund	0.98%
FIXED-INCOME	46.27%	Fixed-Income	35.81%	•	Bond Fund	30.98%
				•	High-Yield Fund	3.42%
				•	Bond Plus Fund	1.41%
		Short-Term Fixed-Income	5.48%	•	Short-Term Bond Fund	5.14%
				•	Money Market Fund	0.34%
		Inflation-Protected Assets	4.98%	•	Inflation-Linked Bond Fund	4.98%
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.

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TIAA-CREF Lifecycle 2015 Fund

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TIAA-CREF Managed Allocation Fund

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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% of its assets in equity Underlying Funds including up to 5% of its assets in real estate Underlying Funds; and (2) approximately 40% 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 10%. 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 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 affect 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 May 31, 2013, are listed in the chart below. These allocations may change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	60.40%	U.S. Equity	43.88%	•	Enhanced Large-Cap Value Index Fund	8.44%
				•	Large-Cap Value Fund	8.30%
				•	Enhanced Large-Cap Growth Index Fund	7.82%
				•	Large-Cap Growth Fund	7.66%
				•	Growth & Income Fund	7.16%
				•	Small-Cap Equity Fund	3.49%
				•	Mid-Cap Value Fund	0.55%
				•	Mid-Cap Growth Fund	0.46%
		International Equity	16.52%	•	International Equity Fund	6.15%
				•	Enhanced International Equity Index Fund	5.01%
				•	Emerging Markets Equity Fund	4.02%
				•	International Opportunities Fund	1.09%
				•	Global Natural Resources Fund	0.25%
FIXED-INCOME	39.60%	Fixed-Income	39.26%	•	Bond Plus Fund	37.25%
				•	High-Yield Fund	2.01%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
Total	100.00%		100.00%			100.00%

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TIAA-CREF Managed Allocation Fund

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TIAA-CREF Lifecycle Index 2025 Fund

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Lifecycle Index 2025 Fund

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 expects to allocate approximately 67.60% of its assets to equity Underlying Funds and 32.40% of its 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 10% 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, the Fund allocates its investments to particular market sectors (U.S. equity, international equity, 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 47.32%; International Equity: 20.28%; Fixed-Income: 30.80%; and Inflation-Protected Assets: 1.60%.

     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); 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	69.80%	U.S. Equity	53.00%	•	Equity Index Fund	53.00%
		International Equity	16.80%	•	International Equity Index Fund	12.70%
				•	Emerging Markets Equity Index Fund	4.10%
FIXED-INCOME	30.20%	Fixed-Income	29.08%	•	Bond Index Fund	29.08%
		Inflation-Protected Assets	1.12%	•	Inflation-Linked Bond Fund	1.12%
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 Lifecycle Index Funds
Years to Target Date	U.S. Equity	International Equity	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	32.00	2.00
5	40.60	17.40	38.00	4.00
0	35.00	15.00	44.00	6.00
-5	31.50	13.50	47.00	8.00
-10	28.00	12.00	50.00	10.00
-15	28.00	12.00	50.00	10.00
-20	28.00	12.00	50.00	10.00
-25	28.00	12.00	50.00	10.00
-30	28.00	12.00	50.00	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.

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TIAA-CREF Lifecycle Index 2025 Fund

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TIAA-CREF Lifecycle 2045 Fund

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Lifecycle 2045 Fund

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 retiring or planning to retire within a few years of 2045.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.88%	U.S. Equity	63.58%	•	Large-Cap Value Fund	12.15%
				•	Enhanced Large-Cap Value Index Fund	12.15%
				•	Large-Cap Growth Fund	11.28%
				•	Enhanced Large-Cap Growth Index Fund	11.25%
				•	Growth & Income Fund	10.20%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.30%	•	International Equity Fund	8.81%
				•	Enhanced International Equity Index Fund	7.67%
				•	Emerging Markets Equity Fund	5.74%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.12%	Fixed-Income	9.78%	•	High-Yield Fund	5.91%
				•	Bond Plus Fund	3.87%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
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.

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TIAA-CREF Lifecycle 2045 Fund

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TIAA-CREF Lifecycle 2035 Fund

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Lifecycle 2035 Fund

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 retiring or planning to retire within a few years of 2035.

     The Fund expects to allocate approximately 83.60% of its assets to equity Underlying Funds and 16.40% of its 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 10% 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 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, the Fund allocates its 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, 2014, which will change over time, are approximately as follows: U.S. Equity: 58.52%; International Equity: 25.08%; Fixed-Income: 16.40%; 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	85.43%	U.S. Equity	60.34%	•	Enhanced Large-Cap Value Index Fund	11.57%
				•	Large-Cap Value Fund	11.47%
				•	Enhanced Large-Cap Growth Index Fund	10.73%
				•	Large-Cap Growth Fund	10.62%
				•	Growth & Income Fund	9.74%
				•	Small-Cap Equity Fund	4.75%
				•	Mid-Cap Value Fund	0.79%
				•	Mid-Cap Growth Fund	0.67%
		International Equity	25.09%	•	International Equity Fund	8.46%
				•	Enhanced International Equity Index Fund	7.27%
				•	Emerging Markets Equity Fund	5.48%
				•	Global Natural Resources Fund	2.33%
				•	International Opportunities Fund	1.55%
FIXED-INCOME	14.57%	Fixed-Income	14.24%	•	High-Yield Fund	5.90%
				•	Bond Plus Fund	5.86%
				•	Bond Fund	2.48%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2035 Fund

XML

TIAA-CREF Lifecycle 2055 Fund

TIAA-CREF Lifecycle 2055 Fund

Lifecycle 2055 Fund

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 retiring or planning to retire within a few years of 2055.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.80%	U.S. Equity	63.58%	•	Large-Cap Value Fund	12.23%
				•	Enhanced Large-Cap Value Index Fund	12.13%
				•	Large-Cap Growth Fund	11.34%
				•	Enhanced Large-Cap Growth Index Fund	11.20%
				•	Growth & Income Fund	10.13%
				•	Small-Cap Equity Fund	5.00%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.22%	•	International Equity Fund	8.71%
				•	Enhanced International Equity Index Fund	7.68%
				•	Emerging Markets Equity Fund	5.76%
				•	Global Natural Resources Fund	2.43%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.20%	Fixed-Income	9.87%	•	High-Yield Fund	5.96%
				•	Bond Plus Fund	3.91%
		Short-Term Fixed-Income	0.33%	•	Money Market Fund	0.33%
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.

XML

TIAA-CREF Lifecycle 2050 Fund

TIAA-CREF Lifecycle 2050 Fund

Lifecycle 2050 Fund

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 retiring or planning to retire within a few years of 2050.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.94%	U.S. Equity	63.64%	•	Large-Cap Value Fund	12.17%
				•	Enhanced Large-Cap Value Index Fund	12.16%
				•	Large-Cap Growth Fund	11.30%
				•	Enhanced Large-Cap Growth Index Fund	11.26%
				•	Growth & Income Fund	10.19%
				•	Small-Cap Equity Fund	5.01%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.30%	•	International Equity Fund	8.79%
				•	Enhanced International Equity Index Fund	7.68%
				•	Emerging Markets Equity Fund	5.75%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.06%	Fixed-Income	9.72%	•	High-Yield Fund	5.88%
				•	Bond Plus Fund	3.84%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
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.

XML

Document and Entity Information	0 Months Ended
	Nov. 30, 2012
Risk/Return:
Document Type	497
Document Period End Date	Nov. 30, 2012
Registrant Name	TIAA-CREF FUNDS
Central Index Key	0001084380
Amendment Flag	false
Document Creation Date	Jul. 11, 2013
Document Effective Date	Jul. 16, 2013
Prospectus Date	Oct. 01, 2012

XML

Label

Element

Value

TIAA-CREF Lifecycle 2050 Fund

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

cik0001084380_SupplementTextBlock

Lifecycle 2050 Fund

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 retiring or planning to retire within a few years of 2050.

     The Fund expects to allocate approximately 90.00% of its assets to equity Underlying Funds and 10.00% of its 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 10% 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 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, the Fund allocates its 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, 2014, 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 and High-Yield 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 May 31, 2013, are listed in the chart below. These allocations will change over time.

Asset Class	Allocation	Market Sector	Allocation	Underlying Funds		Allocation
EQUITY	89.94%	U.S. Equity	63.64%	•	Large-Cap Value Fund	12.17%
				•	Enhanced Large-Cap Value Index Fund	12.16%
				•	Large-Cap Growth Fund	11.30%
				•	Enhanced Large-Cap Growth Index Fund	11.26%
				•	Growth & Income Fund	10.19%
				•	Small-Cap Equity Fund	5.01%
				•	Mid-Cap Value Fund	0.84%
				•	Mid-Cap Growth Fund	0.71%
		International Equity	26.30%	•	International Equity Fund	8.79%
				•	Enhanced International Equity Index Fund	7.68%
				•	Emerging Markets Equity Fund	5.75%
				•	Global Natural Resources Fund	2.44%
				•	International Opportunities Fund	1.64%
FIXED-INCOME	10.06%	Fixed-Income	9.72%	•	High-Yield Fund	5.88%
				•	Bond Plus Fund	3.84%
		Short-Term Fixed-Income	0.34%	•	Money Market Fund	0.34%
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/Return [Heading]

rr_RiskReturnHeading

TIAA-CREF Lifecycle 2050 Fund