Net Unrealized Gains and Losses on Available-for-Sale Investment Securities Reflected as Separate Component of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of Net Unrealized Investment Gains Losses Included in Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gains (losses) on fixed maturity securities without an allowance for credit losses	[1]	$ 10,159	$ 6,676	$ 1,775
Net unrealized gains (losses) on fixed maturity securities with an allowance for credit losses	[1]	(7)	0	0
Adjustments to DAC, PVFP, sales inducements and benefit reserves		(7,302)	(4,789)	(952)
Income taxes, net		(611)	(406)	(190)
Net unrealized investment gains (losses)		2,239	1,481	633
Less: net unrealized investment gains (losses) attributable to noncontrolling interests		25	25	38
Net unrealized investment gains (losses)		$ 2,214	$ 1,456	$ 595	$ 1,085

[1] Excludes foreign exchange.