Investments and Derivative Instruments Level 4 Fair Value Hedges (Details) - Fair Value Hedging [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	[1]	$ 0	$ (3)	$ 6
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge	[1]	0	1	(11)
Gain (Loss) on Investments [Member] | Interest Rate Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net				7
Gain (Loss) on Investments [Member] | Currency Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		0	0	1
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge		0	0	(1)
Benefits, losses and loss adjustment expenses [Member] | Currency Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		0	0	(2)
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge		0	0	2
Designated as Hedging Instrument [Member] | Gain (Loss) on Investments [Member] | Interest Rate Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net		0	(3)
Increase (Decrease) in Fair Value of Hedged Item in Interest Rate Fair Value Hedge		$ 0	$ 1	$ (12)

[1] The amounts presented do not include the periodic net coupon settlements of the derivative or the coupon income (expense) related to the hedged item. The net of the amounts presented represents the ineffective portion of the hedge