REVISION OF PRIOR PERIOD FINANCIAL STATEMENTS - Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flow from operating activities:
Net income (loss)												$ (339)	$ 3,323
Net income (loss)	$ (944)	$ (4,086)	$ 5,750	$ (264)	$ 268	$ (849)	$ 1,664	$ (581)	$ 720	$ (845)	$ (1,884)	(902)	2,791
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Policy charges and fee income	(853)	(824)	(905)	(899)	(863)	(857)	(1,729)	(1,720)	(2,582)	(2,619)	(3,487)	(3,515)	(3,289)
Interest credited to policyholder's account balances	277		289	296	291	272		563	845	859	1,149	979
Net derivative (gains) losses		5,908	(9,532)	343	179	1,558	(3,624)	1,737	(2,097)	2,080	3,831	1,034	(854)
Amortization and depreciation			990			127	1,130	250		271	391	360	850
Capitalization of DAC									(414)	(466)	(648)	(592)
Future policy benefits			1,846			75	1,686	118	1,811	1,075	1,084	(330)	1,197
Reinsurance recoverable			(96)				(149)	(59)		(127)
Current and deferred income taxes			1,465			49	439	94	502	(86)	(329)	(563)
Net cash provided by (used in) operating activities			(609)			(148)	(868)	(283)	(637)	(712)	(606)	1,418	(381)
Cash flows from financing activities:
Change in collateralized pledged assets			44				58		58	3
Change in collateralized pledged liabilities			656				247		(1,981)	(1,898)
Net cash provided by (used in) financing activities			2,492				2,308		7,256	7,228
Cash and cash equivalents	$ 3,962	4,318	7,492	1,553	3,093	2,922	4,318	3,093	$ 3,962	1,553	1,492	2,622	3,409
Net income (loss) from discontinued operations												563	533
As Previously Reported
Cash flow from operating activities:
Net income (loss)												(358)	3,377
Net income (loss)		(4,091)	5,736	(262)	265	(828)	1,645	(563)		(825)	(1,846)	(921)	2,844
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Policy charges and fee income		(825)	(904)	(853)	(865)	(859)	(1,729)	(1,724)		(2,577)	(3,450)	(3,523)	(3,294)
Interest credited to policyholder's account balances			289	280	288	269		557		837	1,127	1,002
Net derivative (gains) losses		5,903	(9,533)	342	178	1,555	(3,630)	1,733		2,075	3,820	1,010	(870)
Amortization and depreciation			1,025			143	1,181	268		267	323	340	825
Capitalization of DAC											(648)	(597)
Future policy benefits			1,817			41	1,666	91		1,035	1,115	(284)	1,189
Reinsurance recoverable			(97)				(149)	(59)		(123)
Current and deferred income taxes			1,462			54	433	99		(81)	(334)	(556)
Net cash provided by (used in) operating activities			(621)			(148)	(868)	(283)		(712)	(606)	1,418	(381)
Cash flows from financing activities:
Change in collateralized pledged assets			45				58
Change in collateralized pledged liabilities			667				247
Net cash provided by (used in) financing activities			2,504				2,308
Cash and cash equivalents		4,318	7,492	1,553	3,093	2,922	4,318	3,093		1,553	1,492	2,622	3,409
Impact of Revisions
Cash flow from operating activities:
Net income (loss)												19	(54)
Net income (loss)		5	14	(2)	3	(21)	19	(18)		(20)	(38)	19	(53)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Policy charges and fee income		1	(1)	(46)	2	2	0	4		(42)	(37)	8	5
Interest credited to policyholder's account balances			0	16	3	3		6		22	22	(23)
Net derivative (gains) losses		5	1	1	1	3	6	4		5	11	24	16
Amortization and depreciation			(35)			(16)	(51)	(18)		4	68	20	25
Capitalization of DAC											0	5
Future policy benefits			29			34	20	27		40	(31)	(46)	8
Reinsurance recoverable			1				0	0		(4)
Current and deferred income taxes			3			(5)	6	(5)		(5)	5	(7)
Net cash provided by (used in) operating activities			12			0	0	0		0	0	0	0
Cash flows from financing activities:
Change in collateralized pledged assets			(1)				0
Change in collateralized pledged liabilities			(11)				0
Net cash provided by (used in) financing activities			(12)				0
Cash and cash equivalents		$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0		$ 0	$ 0	$ 0	$ 0