Gain or Loss Recognized in Income on Non-qualifying Strategies (Detail) (Non-qualifying strategies, USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	$ (224)	$ 1	$ (289)	$ (85)
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	(78)	4	(79)	7
Foreign currency swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	(72)	(33)	(98)	(77)
Credit default swaps
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized within Net Realized Investment Gains (Losses)	$ (74)	$ 30	$ (112)	$ (15)