Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Other-than-temporary impairment losses recognized in earnings	$ 2	$ 18
Corporate and other bonds [Member]
Other-than-temporary impairment losses recognized in earnings	1	3
Residential mortgage-backed [Member]
Other-than-temporary impairment losses recognized in earnings	1
Total fixed maturity securities available-for-sale [Member]
Other-than-temporary impairment losses recognized in earnings	2	3
Preferred stock [Member]
Other-than-temporary impairment losses recognized in earnings		$ 15