Investments and Derivative Instruments Level 4 Fair Value Hedges (Details) (Fair Value Hedging [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	$ (3)	$ 6	$ (17)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	1	(11)	15
Gain (Loss) on Investments [Member] | Interest Rate Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	(3)	7	(4)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	1	(12)	2
Gain (Loss) on Investments [Member] | Currency Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	0	1	(7)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	0	(1)	7
Benefits, losses and loss adjustment expenses [Member] | Currency Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	0	(2)	(6)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	$ 0	$ 2	$ 6