INVESTMENTS - Information Regarding Pretax Net Gains and Losses From Investments (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gain (Loss) on Securities [Line Items]
Loan loss reserves	[1]									$ 0	$ (18)	$ (19)
Total net investment gains (losses)		$ 256	$ 108	$ (170)	$ (463)	$ 12	$ (153)	$ (66)	$ 71	(270)	(135)	(430)
Credit Losses
Fixed maturity securities available for sale	[2]									(75)	(13)	(64)
Fixed maturity securities held to maturity										1	0	0
Commercial mortgage and other loans										(103)	0	0
Loan commitments										(21)	0	0
Reinsurance recoverables and other										(2)	0	0
Total credit losses										(200)	(13)	(64)
Derivatives and Other
Derivative gains (losses)										399	(174)	(224)
Foreign currency gains (losses)										(568)	(62)	(10)
Derivatives and other
Gain (Loss) on Securities [Line Items]
Total net investment gains (losses)										(169)	(236)	(234)
Fixed maturity securities
Gain (Loss) on Securities [Line Items]
Gross gains from sales										31	115	101
Gross losses from sales										(47)	(68)	(156)
Foreign currency gains (losses) on sales and redemptions										(69)	(16)	73
Total net investment gains (losses)										(85)	31	18
Equity securities
Gain (Loss) on Securities [Line Items]
Total net investment gains (losses)										$ 184	$ 101	$ (131)

[1] U.S. GAAP guidance adopted as of January 1, 2020 has superseded these losses, included for comparative purposes only

[2] Includes other-than-temporary impairment losses for prior year