Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Other-than-temporary impairment losses recognized in earnings	$ 5	$ 16	$ 7	$ 34
Corporate and other bonds [Member]
Other-than-temporary impairment losses recognized in earnings	2	5	3	8
Residential mortgage-backed [Member]
Other-than-temporary impairment losses recognized in earnings	1	3	2	3
Other asset-backed [Member]
Other-than-temporary impairment losses recognized in earnings	1	1	1	1
Total asset-backed [Member]
Other-than-temporary impairment losses recognized in earnings	2	4	3	4
Total fixed maturity securities available-for-sale [Member]
Other-than-temporary impairment losses recognized in earnings	4	9	6	12
Common stock [Member]
Other-than-temporary impairment losses recognized in earnings	1	2	1	2
Preferred stock [Member]
Other-than-temporary impairment losses recognized in earnings		5		20
Equity securities [Member]
Other-than-temporary impairment losses recognized in earnings	$ 1	$ 7	$ 1	$ 22