Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) - Universal And Variable Life Contracts - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Secondary Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Account value (general and separate account)	$ 16,994	$ 16,875
Net amount at risk	$ 177,022	$ 180,069
Average attained age of policyholders	57 years	56 years
Paid-Up Guarantees
Net Amount at Risk by Product and Guarantee [Line Items]
Account value (general and separate account)	$ 3,490	$ 3,587
Net amount at risk	$ 19,360	$ 20,344
Average attained age of policyholders	62 years	61 years