Reclassifications In (Out) of Accumulated Other Comprehensive Income (Loss), Net of Taxes (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Net unrealized investment gains (losses), amounts reclassified from (to) OCI, provision for income taxes		$ 4	$ (5)	$ 33	$ 0
Net unrealized investment gains (losses), amounts reclassified from (to) OCI	[1]	(9)	8	(62)	(1)
Derivatives qualifying as hedges, amounts reclassified from (to) OCI	[2]	(18)	(12)	(59)	(39)
Provision for income taxes
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Net unrealized investment gains (losses), amounts reclassified from (to) OCI, provision for income taxes		4	(5)	33	0
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		9	6	31	21
Interest Rate Swaps Hedging Assets | Net Investment (Gains) Losses
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		0	0	(1)	0
Interest Rate Swaps Hedging Assets | Net Investment Income
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		(27)	(22)	(80)	(61)
Inflation indexed swaps | Net Investment (Gains) Losses
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		0	0	(7)	0
Inflation indexed swaps | Net Investment Income
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		0	5	(2)	2
Forward bond purchase commitments | Net Investment Income
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Derivatives qualifying as hedges, amounts reclassified from (to) OCI		0	(1)	0	(1)
Unrealized (gains) losses on investment | Net Investment (Gains) Losses
Accumulated Other Comprehensive Income Loss Net Of Tax [Line Items]
Net unrealized investment gains (losses), amounts reclassified from (to) OCI, before tax	[3]	$ (13)	$ 13	$ (95)	$ (1)

[1] Net of adjustments to DAC, present value of future profits, sales inducements and benefit reserves. See note 4 for additional information.

[2] See note 5 for additional information.

[3] Amounts exclude adjustments to DAC, present value of future profits, sales inducements and benefit reserves.