Variable Annuity and Insurance Guarantees (Distribution of Account Balances by Asset Type) (Details 4) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Mutual funds [Member]
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits [Line Items]
Total mutual funds	$ 71,797	$ 70,953
Equity [Member]
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits [Line Items]
Total mutual funds	41,882	41,403
Bond [Member]
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits [Line Items]
Total mutual funds	25,115	25,060
Other [Member]
Distribution of separate account balances by asset type for variable annuity contracts providing guaranteed benefits [Line Items]
Total mutual funds	$ 4,800	$ 4,490