Label

Element

Value

Risk/Return:

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Registrant Name

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THRIVENT SERIES FUND INC

Prospectus Date

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Apr. 30, 2018

Thrivent Diversified Income Plus Portfolio

Risk/Return:

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Risk/Return [Heading]

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Thrivent Diversified Income Plus Portfolio

Objective [Heading]

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Investment Objective

Objective, Primary [Text Block]

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Thrivent Diversified Income Plus Portfolio (the "Portfolio") seeks to maximize income while maintaining prospects for capital appreciation.

Expense [Heading]

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Fees and Expenses

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Portfolio. If you own a variable annuity contract or variable life insurance contract, you will have additional expenses including mortality and expense risk charges. Please refer to the prospectus for your variable contract for additional information about charges for those contracts.

Shareholder Fees Caption [Text]

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SHAREHOLDER FEES
(fees paid directly from your investment)

Operating Expenses Caption [Text]

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

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

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The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Portfolio shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Portfolio’s performance. During the most recent fiscal year, the Portfolio’s portfolio turnover rate was 146% of the average value of its portfolio.

Portfolio Turnover, Rate

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146.00%

Expense Example [Heading]

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EXAMPLE

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Portfolio is an investment option for variable contracts, and the example does not include charges imposed by variable contracts. If variable contract charges were imposed, your expenses would be higher than those shown. The example assumes that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year, and that the Portfolio’s operating expenses remain the same. Although your actual cost may be higher or lower, based on the foregoing assumptions, your cost would be:

Strategy [Heading]

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Principal Strategies

Strategy Narrative [Text Block]

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Under normal circumstances, the Portfolio invests in a combination of equity securities and debt securities within the ranges shown in the following table:

Broad Asset Category	Target Allocation	Allocation Range
Debt Securities	70%	50-90%
Equity Securities	30%	10-50%

The equity securities in which the Portfolio invests are primarily income-producing and may include common stock, preferred stock, securities convertible into common stock, or securities or other instruments the price of which is linked to the value of common stock. Under normal circumstances, the Portfolio intends to invest in real estate investment trusts (“REITs”).

The debt securities in which the Portfolio invests may be of any maturity or credit quality, including high yield, high risk bonds, notes, debentures and other debt obligations commonly known as “junk bonds.” At the time of purchase, these high-yield securities are rated within or below the “BB” major rating category by S&P or the “Ba” major rating category by Moody’s or are unrated but considered to be of comparable quality by the Adviser. The Portfolio may also invest in leveraged loans, which are senior secured loans that are made by banks or other lending institutions to companies that are rated below investment grade. In addition, the Portfolio may invest in investment-grade corporate bonds, asset-backed securities, mortgage-backed securities (including commercially backed ones), convertible bonds, and sovereign and emerging market debt (both U.S. dollar and non-U.S. dollar denominated).

The Portfolio may utilize derivatives (such as futures and swaps) for investment exposure or hedging purposes, including credit default swap agreements on security indexes. The Portfolio may enter into standardized derivatives contracts traded on domestic or foreign securities exchanges, boards of trade, or similar entities, and non-standardized derivatives contracts traded in the over-the-counter market.

The Portfolio may invest in foreign securities, including those of issuers in emerging markets. An “emerging market” country is any country determined by the Adviser to have an emerging market economy, considering factors such as the country’s credit rating, its political and economic stability and the development of its financial and capital markets.

The Portfolio may invest in exchange-traded funds (“ETFs”), which are investment companies generally designed to track the performance of a securities or other index or benchmark.

The Portfolio may also pursue its investment strategy by investing in other mutual funds, including funds managed by the Adviser or an affiliate.

The Adviser uses fundamental, quantitative and technical investment research techniques to determine what to buy and sell. Fundamental techniques assess a security’s value based on an issuer’s financial profile, management, and business prospects while quantitative and technical techniques involve a more data-oriented analysis of financial information, market trends and price movements.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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The Portfolio is subject to the following principal investment risks. Shares of the Portfolio will rise and fall in value and there is a risk that you could lose money by investing in the Portfolio. The Portfolio cannot be certain that it will achieve its investment objective.

Allocation Risk. The Portfolio’s investment performance depends upon how its assets are allocated across broad asset categories and applicable sub-classes within such categories. Some broad asset categories and sub-classes may perform below expectations or the securities markets generally over short and extended periods. In particular, underperformance in the fixed income markets would have a material adverse effect on the Portfolio's total return given its significant allocation to fixed income securities. Therefore, a principal risk of investing in the Portfolio is that the allocation strategies used and the allocation decisions made will not produce the desired results.

Convertible Securities Risk. Convertible securities are subject to the usual risks associated with debt securities, such as interest rate risk and credit risk. Convertible securities also react to changes in the value of the common stock into which they convert, and are thus subject to market risk. The Portfolio may also be forced to convert a convertible security at an inopportune time, which may decrease the Portfolio’s return.

Credit Risk. Credit risk is the risk that an issuer of a debt security to which the Portfolio is exposed may no longer be able or willing to pay its debt. As a result of such an event, the debt security may decline in price and affect the value of the Portfolio.

Derivatives Risk. The use of derivatives (such as futures and credit default swaps) involves additional risks and transaction costs which could leave the Portfolio in a worse position than if it had not used these instruments. The use of derivatives can lead to losses because of adverse movements in the price or value of the underlying asset, index or rate, which may be magnified by certain features of the contract. Changes in the value of the derivative may not correlate as intended with the underlying asset, rate or index, and the Portfolio could lose much more than the original amount invested. Derivatives can be highly volatile, illiquid and difficult to value. Certain derivatives may also be subject to counterparty risk, which is that the other party in the transaction will not fulfill its contractual obligations due to its financial condition, market events, or other reasons.

Emerging Markets Risk. The economic and political structures of developing countries, in most cases, do not compare favorably with the U.S. or other developed countries in terms of wealth and stability, and their financial markets often lack liquidity. Portfolio performance will likely be negatively affected by portfolio exposure to countries in the midst of, among other things, hyperinflation, currency devaluation, trade disagreements, sudden political upheaval, or interventionist government policies. Significant buying or selling actions by a few major investors may also heighten the volatility of emerging markets. These factors make investing in emerging market countries significantly riskier than in other countries, and events in any one country could cause the Portfolio’s share price to decline.

ETF Risk. An ETF is subject to the risks of the underlying investments that it holds. In addition, for index-based ETFs, the performance of an ETF may diverge from the performance of such index (commonly known as tracking error). ETFs are subject to fees and expenses (like management fees and operating expenses) that do not apply to an index, and the Portfolio will indirectly bear its proportionate share of any such fees and expenses paid by the ETFs in which it invests.

Foreign Securities Risk. Foreign securities are generally more volatile than their domestic counterparts, in part because of higher political and economic risks, lack of reliable information and fluctuations in currency exchange rates. Foreign securities may also be more difficult to resell than comparable U.S. securities because the markets for foreign securities are often less liquid. Even when a foreign security increases in price in its local currency, the appreciation may be diluted by adverse changes in exchange rates when the security’s value is converted to U.S. dollars. Foreign withholding taxes also may apply and errors and delays may occur in the settlement process for foreign securities. All of these risks may be heightened for securities of issuers located in, or with significant operations in, emerging market countries.

High Yield Risk. High yield securities – commonly known as “junk bonds” – to which the Portfolio is exposed are considered predominantly speculative with respect to the issuer’s continuing ability to make principal and interest payments. If the issuer of the security is in default with respect to interest or principal payments, the value of the Portfolio may be negatively affected.

Interest Rate Risk. Interest rate risk is the risk that prices of debt securities decline in value when interest rates rise for debt securities that pay a fixed rate of interest. Debt securities with longer durations (a measure of price sensitivity of a bond or bond fund to changes in interest rates) or maturities (i.e., the amount of time until a bond’s issuer must pay its principal or face value) tend to be more sensitive to changes in interest rates than debt securities with shorter durations or maturities. In addition, both mortgage-backed and asset-backed securities are sensitive to changes in the repayment patterns of the underlying security. If the principal payment on the underlying asset is repaid faster or slower than the holder of the asset-backed or mortgage-backed security anticipates, the price of the security may fall, particularly if the holder must reinvest the repaid principal at lower rates or must continue to hold the security when interest rates rise. This effect may cause the value of the Portfolio to decline and reduce the overall return of the Portfolio. Changes by the Federal Reserve to monetary policies could affect interest rates and the value of some securities.

Investment Adviser Risk. The Portfolio is actively managed and the success of its investment strategy depends significantly on the skills of the Adviser in assessing the potential of the investments in which the Portfolio invests. This assessment of investments may prove incorrect, resulting in losses or poor performance, even in rising markets.

Issuer Risk. Issuer risk is the possibility that factors specific to a company to which the Portfolio is exposed will affect the market prices of the company’s securities and therefore the value of the Portfolio. Common stock of a company is subordinate to other securities issued by the company. If a company becomes insolvent, interests of investors owning common stock will be subordinated to the interests of other investors in, and general creditors of, the company.

Leveraged Loan Risk. Leveraged loans (also known as bank loans) are subject to the risks typically associated with debt securities. In addition, leveraged loans, which typically hold a senior position in the capital structure of a borrower, are subject to the risk that a court could subordinate such loans to presently existing or future indebtedness or take other action detrimental to the holders of leveraged loans. Leveraged loans are also subject to the risk that the value of the collateral, if any, securing a loan may decline, be insufficient to meet the obligations of the borrower, or be difficult to liquidate. Some leveraged loans are not as easily purchased or sold as publicly-traded securities and others are illiquid, which may make it more difficult for the Portfolio to value them or dispose of them at an acceptable price. Below investment-grade leveraged loans are typically more credit sensitive. In the event of fraud or misrepresentation, the Portfolio may not be protected under federal securities laws with respect to leveraged loans that may not be in the form of “securities.” The settlement period for some leveraged loans may be more than seven days.

Liquidity Risk. Liquidity is the ability to sell a security relatively quickly for a price that most closely reflects the actual value of the security. High-yield bonds and leveraged loans have a less liquid resale market. In addition, dealer inventories of bonds are at or near historic lows in relation to market size, which has the potential to decrease liquidity and increase price volatility in the fixed income markets, particularly during periods of economic or market stress. As a result, the Adviser may have difficulty selling or disposing of securities quickly in certain markets or may only be able to sell the holdings at prices substantially less than what the Adviser believes they are worth.

Market Risk. Over time, securities markets generally tend to move in cycles with periods when security prices rise and periods when security prices decline. The value of the Portfolio’s investments may move with these cycles and, in some instances, increase or decrease more than the applicable market(s) as measured by the Portfolio’s benchmark index(es). The securities markets may also decline because of factors that affect a particular industry.

Mortgage-Related and Other Asset-Backed Securities Risk. The value of mortgage-related and asset-backed securities will be influenced by the factors affecting the housing market and the assets underlying such securities. As a result, during periods of declining asset value, difficult or frozen credit markets, swings in interest rates, or deteriorating economic conditions, mortgage-related and asset-backed securities may decline in value, face valuation difficulties, become more volatile and/or become illiquid.

Other Funds Risk. The performance of the Portfolio is dependent, in part, upon the performance of other funds manged by the Adviser or an affiliate (“Other Funds”) in which the Portfolio may invest. As a result, the Portfolio is subject to the same risks as those faced by the Other Funds.

Portfolio Turnover Rate Risk. The Portfolio may engage in active and frequent trading of portfolio securities in implementing its principal investment strategies. A high rate of portfolio turnover (100% or more) involves correspondingly greater expenses which are borne by the Portfolio and its shareholders and may also result in short-term capital gains taxable to shareholders.

Preferred Securities Risk. There are certain additional risks associated with investing in preferred securities, including, but not limited to, preferred securities may include provisions that permit the issuer, at its discretion, to defer or omit distributions for a stated period without any adverse consequences to the issuer; preferred securities are generally subordinated to bonds and other debt instruments in a company’s capital structure in terms of having priority to corporate income and liquidation payments, and therefore will be subject to greater credit risk than more senior debt instruments; preferred securities may be substantially less liquid than many other securities, such as common stocks or U.S. Government securities; generally, traditional preferred securities offer no voting rights with respect to the issuing company unless preferred dividends have been in arrears for a specified number of periods, at which time the preferred security holders may elect a number of directors to the issuer’s board; and in certain varying circumstances, an issuer of preferred securities may redeem the securities prior to a specified date.

Real Estate Investment Trust (“REIT”) Risk. REITs generally can be divided into three types: equity REITs, mortgage REITs, and hybrid REITs (which combine the characteristics of equity REITs and mortgage REITs). Equity REITs will be affected by changes in the values of, and income from, the properties they own, while mortgage REITs may be affected by the credit quality of the mortgage loans they hold. All REIT types may be affected by changes in interest rates. REITs are subject to additional risks, including the fact that they are dependent on specialized management skills that may affect the REITs’ abilities to generate cash flows for operating purposes and for making investor distributions. REITs may have limited diversification and are subject to the risks associated with obtaining financing for real property. As with any investment, there is a risk that REIT securities and other real estate industry investments may be overvalued at the time of purchase. In addition, a REIT can pass its income through to its investors without any tax at the entity level if it complies with various requirements under the Internal Revenue Code. There is the risk, however, that a REIT held by the Portfolio will fail to qualify for this tax-free pass-through treatment of its income. In addition, due to recent changes in the tax laws, certain tax benefits of REITs may not be passed through to mutual fund shareholders. By investing in REITs indirectly through the Portfolio, in addition to bearing a proportionate share of the expenses of the Portfolio, you will also indirectly bear similar expenses of the REITs in which the Portfolio invests.

Volatility Risk. Volatility risk is the risk that certain types of securities shift in and out of favor depending on market and economic conditions as well as investor sentiment. The value of the Portfolio’s shares may be affected by weak equity markets or changes in interest rate or bond yield levels. As a result, the value of the Portfolio’s shares may fluctuate significantly in the short term.

Risk Lose Money [Text]

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Shares of the Portfolio will rise and fall in value and there is a risk that you could lose money by investing in the Portfolio.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

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The following bar chart and table provide an indication of the risks of investing in the Portfolio by showing changes in the Portfolio’s performance from year to year and by showing how the Portfolio’s average annual returns for one-, five- and ten-year periods compared to broad-based securities market indices. These indices are the MSCI World Index—USD Net Returns, which measures the performance of stock markets in developed countries throughout the world, the Bloomberg Barclays U.S. Mortgage-Backed Securities Index, which covers the mortgage-backed securities component of the Bloomberg Barclays U.S. Aggregate Bond Index, the Bloomberg Barclays U.S. High Yield Ba/B 2% Issuer Capped Index, which represents the performance of high yield corporate bonds rated Ba or B, with a maximum allocation of 2% to any one issuer, and the S&P/LSTA Leveraged loan Index, which reflects the performance of the largest facilities in the leveraged loan market.

Call 800-847-4836 or visit Thrivent.com for performance results current to the most recent month-end.

The bar chart and table include the effects of Portfolio expenses, but not charges or deductions against your variable contract, and assume that you sold your investment at the end of the period. Because shares of the Portfolio are offered through variable life insurance and variable annuity contracts, you should carefully review the variable contract prospectus for information on applicable charges and expenses. If the charges and deductions against your variable contract were included, returns would be lower than those shown.

How a Portfolio has performed in the past is not necessarily an indication of how it will perform in the future. Performance information provides some indication of the risks of investing in the Portfolio by showing changes in the Portfolio’s performance over time.

Performance Information Illustrates Variability of Returns [Text]

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The following bar chart and table provide an indication of the risks of investing in the Portfolio by showing changes in the Portfolio’s performance from year to year and by showing how the Portfolio’s average annual returns for one-, five- and ten-year periods compared to broad-based securities market indices.

Performance Additional Market Index [Text]

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These indices are the MSCI World Index—USD Net Returns, which measures the performance of stock markets in developed countries throughout the world, the Bloomberg Barclays U.S. Mortgage-Backed Securities Index, which covers the mortgage-backed securities component of the Bloomberg Barclays U.S. Aggregate Bond Index, the Bloomberg Barclays U.S. High Yield Ba/B 2% Issuer Capped Index, which represents the performance of high yield corporate bonds rated Ba or B, with a maximum allocation of 2% to any one issuer, and the S&P/LSTA Leveraged loan Index, which reflects the performance of the largest facilities in the leveraged loan market.

Performance Availability Phone [Text]

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800-847-4836

Performance Availability Website Address [Text]

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Thrivent.com

Performance Past Does Not Indicate Future [Text]

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How a Portfolio has performed in the past is not necessarily an indication of how it will perform in the future.

Bar Chart [Heading]

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YEAR-BY-YEAR TOTAL RETURN
Annual Return (%)

Bar Chart Does Not Reflect Sales Loads [Text]

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The bar chart and table include the effects of Portfolio expenses, but not charges or deductions against your variable contract, and assume that you sold your investment at the end of the period. Because shares of the Portfolio are offered through variable life insurance and variable annuity contracts, you should carefully review the variable contract prospectus for information on applicable charges and expenses. If the charges and deductions against your variable contract were included, returns would be lower than those shown.

Bar Chart Closing [Text Block]

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Best Quarter:	Q2 '09	+15.49%
Worst Quarter:	Q4 '08	(16.46)%

Performance Table Heading

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AVERAGE ANNUAL TOTAL RETURNS
(PERIODS ENDING DECEMBER 29, 2017)

Thrivent Diversified Income Plus Portfolio | Class A

Risk/Return:

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Maximum Sales Charge (load) Imposed On Purchases (as a percentage of offering price)

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Maximum Deferred Sales Charge (load) (as a percentage of the net asset value at time of purchase or redemption, whichever is lower)

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Management Fees

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0.40%

Other Expenses

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0.07%

Acquired Fund Fees and Expenses

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0.07%

Total Annual Portfolio Operating Expenses

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0.54%

1 Year

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$ 55

3 Years

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173

5 Years

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302

10 Years

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$ 677

2008

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(23.30%)

2009

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33.06%

2010

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15.85%

2011

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2.31%

2012

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14.48%

2013

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11.17%

2014

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4.27%

2015

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0.08%

2016

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7.08%

2017

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9.34%

Highest Quarterly Return, Label

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Best Quarter:

Highest Quarterly Return, Date

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Jun. 30, 2009

Highest Quarterly Return

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15.49%

Lowest Quarterly Return, Label

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Worst Quarter:

Lowest Quarterly Return, Date

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Dec. 31, 2008

Lowest Quarterly Return

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(16.46%)

1 Year

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9.34%

5 Years

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6.32%

10 Years

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6.53%

Thrivent Diversified Income Plus Portfolio | MSCI World Index-USD Net Returns (reflects no deduction for fees, expenses or taxes)

Risk/Return:

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1 Year

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22.40%

5 Years

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11.64%

10 Years

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5.03%

Thrivent Diversified Income Plus Portfolio | Bloomberg Barclays U.S. Mortgage-Backed Securities Index (reflects no deduction for fees, expenses or taxes)

Risk/Return:

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1 Year

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2.47%

5 Years

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2.04%

10 Years

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3.84%

Thrivent Diversified Income Plus Portfolio | Bloomberg Barclays U.S. High Yield Ba/B 2% Issuer Capped Index (reflects no deduction for fees, expenses or taxes)

Risk/Return:

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1 Year

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6.92%

5 Years

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5.45%

10 Years

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7.45%

Thrivent Diversified Income Plus Portfolio | S&P/LSTA Leveraged Loan Index (reflects no deduction for fees, expenses or taxes)

Risk/Return:

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1 Year

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4.12%

5 Years

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4.03%

10 Years

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4.85%