Insurance (Guarantees Related to Universal and Variable Life Contracts) (Details) (Universal and Variable Life Contracts [Member], Secondary Guarantees [Member], USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Universal and Variable Life Contracts [Member] | Secondary Guarantees [Member]
Net Amount at Risk by Product and Guarantee [Line Items]
Account value (general and separate account)	$ 6,079	$ 5,812
Net amount at risk	$ 89,733	$ 86,468
Average attained age of policyholders	58 years	58 years