Variable Annuity and Insurance Guarantees (Separate Account Balance by Type) (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Mutual funds
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	$ 70,953	$ 69,478
Equity
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	41,403	39,195
Bond
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	25,060	26,519
Other
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits:
Total mutual funds	$ 4,490	$ 3,764