Variable Annuity and Insurance Guarantees (Separate Account Balances by Type) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Mutual funds
Variable Annuity and Insurance Guarantees
Total mutual funds	$ 70,641	$ 69,090
Equity [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	42,276	40,622
Bond [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	23,220	23,142
Other [Member]
Variable Annuity and Insurance Guarantees
Total mutual funds	$ 5,145	$ 5,326