Gain or Loss Recognized in Income on Non-qualifying Strategies (Detail) (Non-qualifying strategies, USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	$ (27)	$ (106)	$ (53)	$ (86)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	4	8	(1)	3
Foreign currency swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	3	(48)	(26)	(44)
Credit default swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	(43)	(66)	(38)	(45)
Others
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	$ 9		$ 12