Guaranteed Benefit Features (Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts) (Details) (Variable Annuity [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 88,235	$ 81,670
Percent of total variable annuity separate account values	98.00%	98.00%
Domestic equity
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	41,066	37,899
International equity
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	15,822	14,850
Bonds
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	22,383	21,174
Money Market
Account Balances Of Variable Annuity Contracts With Guarantees Invested In Separate Accounts [Line Items]
Total	$ 8,964	$ 7,747