Investments (Details 7) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fixed maturities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	$ 36	$ 44	$ 55
Gross losses	(2)	(5)	(4)
Equity securities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	53	193	196
Gross losses	$ 0	$ 0	$ (4)