Investments - Impairments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Impairments Table Details [Abstract]
Credit-related	$ (8)	[1]	$ (9)	[1]	$ (8)	[1]	$ (14)	[1]
Other	(8)		(1)		(8)		(2)
Total	$ (16)		$ (10)		$ (16)		$ (16)

[1] Credit related losses include other-than-temporary declines in fair value of fixed maturities and changes in valuation reserves and asset write-downs related to commercial mortgage loans and real estate entities. There were no credit losses on fixed maturities for which a portion of the impairment was recognized in other comprehensive income.