Variable Annuity and Insurance Guarantees (Separate Account Balance by Type) (Details 5) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Mutual funds
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	$ 68,747	$ 70,953
Equity
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	39,806	41,403
Bond
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	23,700	25,060
Other
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	$ 5,241	$ 4,490