Derivatives (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	$ (135)	$ 981	$ 149
Net Derivatives Gains (Losses) Recognized for Hedged Items	127	(1,005)	(160)
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	(8)	(24)	(11)
Interest rate swaps [Member] | Fixed maturity securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	(4)	(25)	(14)
Net Derivatives Gains (Losses) Recognized for Hedged Items	0	22	16
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	(4)	(3)	2
Interest rate swaps [Member] | Policyholder account balances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	(82)	1,054	140
Net Derivatives Gains (Losses) Recognized for Hedged Items	96	(1,030)	(142)
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	14	24	(2)
Foreign currency swaps [Member] | Foreign-denominated fixed maturity securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	(1)	1	14
Net Derivatives Gains (Losses) Recognized for Hedged Items	1	3	(14)
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	0	4	0
Foreign currency swaps [Member] | Foreign-denominated policyholder account balances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	3	(24)	9
Net Derivatives Gains (Losses) Recognized for Hedged Items	(20)	(25)	(20)
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	(17)	(49)	(11)
Foreign currency forwards [Member] | Foreign-denominated fixed maturity securities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net Derivatives Gains (Losses) Recognized for Derivatives	(51)	(25)	0
Net Derivatives Gains (Losses) Recognized for Hedged Items	50	25	0
Ineffectiveness Recognized in Net Derivatives Gains (Losses)	$ (1)	$ 0	$ 0