Guaranteed Benefit Features (Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts) (Details) - Variable Annuity [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 106,064	$ 106,293
Percent of total variable annuity separate account values	99.00%	99.00%
Domestic equity
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 48,364	$ 48,362
International equity
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	18,060	18,382
Bonds
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	26,485	26,492
Money Market
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 13,155	$ 13,057