Variable Annuity and Insurance Guarantees (Separate Account Balances by Type) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Mutual funds
Variable Annuity and Insurance Guarantees
Total mutual funds	$ 68,675	$ 68,747
Equity [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	39,138	39,806
Bond [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	23,818	23,700
Other [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	$ 5,719	$ 5,241