Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) (Universal And Variable Life Contracts, USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Secondary Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Account value (general and separate account)	$ 17,072	$ 16,875
Net amount at risk	178,870	180,069
Average attained age of policyholders	56 years	56 years
Paid-Up Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Account value (general and separate account)	3,556	3,587
Net amount at risk	$ 19,980	$ 20,344
Average attained age of policyholders	61 years	61 years