Investments - Impairments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Impairments Table Details [Abstract]
Credit-related	$ 0	[1]	$ (5)	[1]
Other	0		(1)
Total	$ 0		$ (6)

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