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	$ (2)	$ 26	$ (16)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	4	(23)	10
Gain (Loss) on Investments [Member] | Interest Rate Swap [Member]
Fair Value Hedges [Line Items]
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net	(2)	27	(3)
Derivative Instruments Gain (Loss) Recognized in Income on Hedged Item Net	4	(24)	(3)
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