Investments (Details 7) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fixed maturities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	$ 38	$ 36	$ 44
Gross losses	(7)	(2)	(5)
Equity securities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	99	53	193
Gross losses	$ (5)	$ 0	$ 0