Guaranteed Benefit Features (Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts) (Details) - Variable Annuity [Member] - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 103,664	$ 107,866
Percent of total variable annuity separate account values	99.00%	99.00%
Domestic equity [Member]
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 46,446	$ 49,569
International equity [Member]
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	17,826	18,791
Bonds [Member]
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	26,551	26,808
Money Market [Member]
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 12,841	$ 12,698