SIGNIFICANT ACCOUNTING POLICIES - Assumption Updates and Model Changes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Accounting Estimate [Line Items]
Policy charges and fee income	$ 3,464	$ 3,487	$ 3,515
Policyholders’ benefits	4,951	4,088	2,960
Interest credited to policyholders’ account balances	1,118	1,149	979
Net derivative gains (losses)	(1,541)	(3,831)	(1,034)
Amortization of deferred policy acquisition costs, net	1,333	520	451
Income (loss) from operations, before income taxes	(1,386)	(2,463)	(1,472)
Net income (loss)	(759)	(1,884)	(902)
Long-term Lapses Partial Withdrawal Rates And Election Assumptions Updates
Change in Accounting Estimate [Line Items]
Policy charges and fee income	(33)	(11)	(12)
Policyholders’ benefits	1,500	886	684
Interest credited to policyholders’ account balances	2	(14)
Net derivative gains (losses)	106	548	1,100
Amortization of deferred policy acquisition costs, net	866	(77)	(165)
Income (loss) from operations, before income taxes	(2,200)	(1,400)	(228)
Net income (loss)	(1,800)	$ (1,100)	$ (187)
Economic Scenario Generator
Change in Accounting Estimate [Line Items]
Income (loss) from operations, before income taxes	165
Net income (loss)	$ 130
5-year Historical Average Over A 10-year Period
Change in Accounting Estimate [Line Items]
Interest rate assumptions	2.25%