Insurance (Guarantees Related to Annuity Contracts) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Variable Annuity Guarantees | Guaranteed Death Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Account value	$ 197,400	$ 196,595
Separate account value in event of death	165,322	163,566
Net amount at risk in event of death	3,892	4,230
Average attained age of contractholders	65 years	65 years
Variable Annuity Guarantees | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Account value	99,960	99,000
Separate account value at annuitization	96,933	95,963
Net amount at risk at annuitization	1,996	1,770
Average attained age of contractholders	66 years	65 years
Two Tier and Other Annuities | Guaranteed Annuitization Benefits
Net Amount at Risk by Product and Guarantee [Line Items]
Account value	939	1,040
Net amount at risk at annuitization	$ 301	$ 340
Average attained age of contractholders	50 years	50 years