Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Apr. 30, 2012
Bond & Mortgage Securities Account (Prospectus Summary) | Bond & Mortgage Securities Account
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	Bond & Mortgage Securities Account
Investment Objective, Heading	rr_ObjectiveHeading	Objective:
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Account seeks to provide current income.
Expense, Heading	rr_ExpenseHeading	Fees and Expenses of the Account
Expense, Narrative	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Account. These fees and expenses do not reflect the fees and expenses of any variable insurance contract that may invest in the Account and would be higher if they did.
Operating Expenses, Caption	rr_OperatingExpensesCaption	Annual Account Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover, Heading	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover	rr_PortfolioTurnoverTextBlock	The Account 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. These costs, which are not reflected in annual Account operating expenses or in the example, affect the Account's performance. During the most recent fiscal year, the Account's portfolio turnover rate was 252.1% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	252.10%
Expense Example, Heading	rr_ExpenseExampleHeading	Example
Expense Example, Narrative	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Account with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Account 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 Account's operating expenses remain the same. If separate account expenses and contract level expenses were included, expenses would be higher. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	Principal Investment Strategies
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	Under normal circumstances, the Account invests at least 80% of its net assets in intermediate maturity fixed-income or debt securities rated BBB- or higher by Standard & Poor's Rating Service ("S&P") or Baa3 or higher by Moody's Investors Service, Inc. ("Moody's") at the time of purchase, including securities issued or guaranteed by the U.S. government or its agencies or instrumentalities; asset-backed securities or mortgage-backed securities representing an interest in a pool of mortgage loans or other assets; debt securities and taxable municipal bonds; and debt securities issued or guaranteed by foreign governments payable in U.S. dollars. The Account may also invest in foreign securities, and up to 20% of its assets in non-investment grade securities ("junk bonds) which are securities rated BB+ or lower by S&P or Ba1 or lower by Moody's at the time of purchase. Under normal circumstances, the Account maintains an average portfolio duration that is within ±15% or ±0.75 year (whichever is greater) of the duration of the Barclays Capital Aggregate Bond Index, which as of December 31, 2011 was 4.9 years. The Account may actively trade securities and enter into dollar roll transactions which may involve leverage. The Account may utilize derivative strategies. Specifically, the Account may invest in Treasury futures or interest rate swaps to manage the fixed-income exposure and credit default swaps to increase or decrease, in an efficient manner, exposures to certain sectors or individual issuers. The Account may use forwards to manage its foreign currency exposure. During the fiscal year ended December 31, 2011, the average ratings of the Account's fixed-income assets, based on market value at each month-end, were as follows (all ratings are by Moody's): 50.60% in securities rated Aaa  7.12% in securities rated Ba   0.02% in securities rated C 5.22% in securities rated Aa    5.81% in securities rated B    0.00% in securities rated D 11.62% in securities rated A    2.09% in securities rated Caa  1.39% in securities not rated 16.12% in securities rated Baa  0.01% in securities rated Ca
Risk, Heading	rr_RiskHeading	Principal Risks
Risk, Narrative	rr_RiskNarrativeTextBlock	The Account may be an appropriate investment for investors seeking diversification by investing in a fixed-income mutual fund. The value of your investment in the Account changes with the value of the Account's investments. Many factors affect that value, and it is possible to lose money by investing in the Account. An investment in the Account is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks of investing in the Account, in alphabetical order, are: Active Trading Risk. Actively trading portfolio securities may accelerate realization of taxable gains and losses, lower fund performance and may result in high portfolio turnover rates and increased brokerage costs Counterparty Risk. Counterparty risk is the risk that the counterparty to a derivatives contract or repurchase agreement, the borrower of a portfolio's securities, or other obligation, will be unable or unwilling to make timely principal, interest, or settlement payments, or otherwise to honor its obligations. Currency Risk.  Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions. Derivatives Risk. Transactions in derivatives (such as options, futures, currency contracts, and swaps) may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so and produce disproportionate losses. Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate risk and credit quality risk. The market value of fixed-income securities generally declines when interest rates rise, and an issuer of fixed-income securities could default on its payment obligations. Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies). High Yield Securities Risk. High yield fixed-income securities (commonly referred to as "junk bonds") are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative. Leverage Risk. Leverage created by borrowing or certain types of transactions or investments, such as reverse repurchase agreements, loans of portfolio securities, and the use of when-issued, delayed delivery or forward commitment transactions, or derivative instruments, may impair the fund's liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the fund's net asset value, or diminish the fund's performance. Municipal Securities Risk. Principal and interest payments on municipal securities may not be guaranteed by the issuing body and may be payable only from a particular source. That source may not perform as expected and payment obligations may not be made or made on time. Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund's average portfolio duration, the more sensitive the fund will be to changes in interest rates. Prepayment Risk. Unscheduled prepayments on mortgage-backed and asset-backed securities may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk). Real Estate Securities Risk. Real estate securities are subject to the risks associated with direct ownership of real estate, including declines in value, adverse economic conditions, increases in expenses, regulatory changes and environmental problems. Risk of Being an Underlying Fund. An underlying fund of a fund of funds may experience relatively large redemptions or investments as the fund of funds periodically reallocates or rebalances its assets. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.    U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. U.S. Government Sponsored Securities Risk. Securities issued by U.S. government-sponsored or -chartered enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. Treasury.
Risk, Lose Money	rr_RiskLoseMoney	Many factors affect that value, and it is possible to lose money by investing in the Account.
Risk, Not Insured Depository Institution	rr_RiskNotInsuredDepositoryInstitution	An investment in the Account is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	Performance
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The following information provides some indication of the risks of investing in the Account by showing changes in the Account's performance from year to year and by showing how the Account's average annual returns for 1, 5, and 10 years (or, if shorter, the life of the Account) compare with those of one or more broad measures of market performance. Past performance is not necessarily an indication of how the Account will perform in the future. Performance figures for the Accounts do not include any separate account expenses, cost of insurance, or other contract-level expenses; total returns for the Accounts would be lower if such expenses were included.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following information provides some indication of the risks of investing in the Account by showing changes in the Account's performance from year to year and by showing how the Account's average annual returns for 1, 5, and 10 years (or, if shorter, the life of the Account) compare with those of one or more broad measures of market performance.
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	Past performance is not necessarily an indication of how the Account will perform in the future.
Bar Chart, Heading	rr_BarChartHeading	Calendar Year Total Returns (%) as of 12/31 each year (Class 1 Shares)
Bar Chart, Closing	rr_BarChartClosingTextBlock	Highest return for a quarter during the period of the bar               chart above:                                                    Q3 '09     9.32% Lowest return for a quarter during the period of the bar                chart above:                                                    Q4 '08    -8.24%
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses, or taxes
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns (%) For the periods ended December 31, 2011
Bond & Mortgage Securities Account (Prospectus Summary) | Bond & Mortgage Securities Account | Barclays Capital Aggregate Bond Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Barclays Capital Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	7.84%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	6.50%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	5.78%
Bond & Mortgage Securities Account (Prospectus Summary) | Bond & Mortgage Securities Account | Class 1
Risk Return [Abstract]	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.44%
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Account Operating Expenses	rr_ExpensesOverAssets	0.45%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	46
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	144
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	252
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	567
Annual Return 2002	rr_AnnualReturn2002	9.26%
Annual Return 2003	rr_AnnualReturn2003	4.59%
Annual Return 2004	rr_AnnualReturn2004	4.98%
Annual Return 2005	rr_AnnualReturn2005	2.50%
Annual Return 2006	rr_AnnualReturn2006	4.65%
Annual Return 2007	rr_AnnualReturn2007	3.41%
Annual Return 2008	rr_AnnualReturn2008	(17.06%)
Annual Return 2009	rr_AnnualReturn2009	20.91%
Annual Return 2010	rr_AnnualReturn2010	11.65%
Annual Return 2011	rr_AnnualReturn2011	7.07%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest return for a quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	9.32%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest return for a quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2008
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(8.24%)
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Bond & Mortgage Securities Account - Class 1
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	7.07%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.39%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	4.78%