REVISION OF PRIOR PERIOD FINANCIAL STATEMENTS - Comprehensive Income (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
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)	$ (705)	$ (3,933)	$ 5,425	$ (306)	$ 428	$ (739)	$ 1,492	$ (311)	$ 787	$ (617)	$ (1,467)	$ 2,189	$ 1,201
Foreign currency translation adjustment	16			(12)					1	(12)	5	(32)	39
Change in unrealized gains (losses), net of reclassification adjustment	229		1,430	746	1,292	836		2,128	3,273	2,874	2,258	(1,326)	672
Other comprehensive income (loss)	266	1,642	1,437	752	1,311	884	3,079	2,195	3,345	2,947	2,248	(1,169)	811
Comprehensive income (loss)	(439)	(2,291)	6,862	446	1,739	145	4,571	1,884	4,132	2,330	781	1,020	2,012
Comprehensive income (loss) attributable to Holdings	$ (519)	(2,380)	6,833	383	1,673	80	4,453	1,753	$ 3,934	2,136	488	671	1,570
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)		(3,942)	5,447	(316)	430	(709)	1,505	(279)		(595)	(1,436)	2,154	1,257
Foreign currency translation adjustment											5	(37)	42
Change in unrealized gains (losses), net of reclassification adjustment			1,434	581	1,369	834		2,203		2,784	2,242	(1,329)	690
Other comprehensive income (loss)		1,642	1,441	587	1,388	882	3,083	2,270		2,857	2,232	(1,177)	832
Comprehensive income (loss)		(2,300)	6,888	271	1,818	173	4,588	1,991		2,262	796	977	2,089
Comprehensive income (loss) attributable to Holdings		(2,389)	6,859	208	1,752	108	4,470	1,860		2,068	503	628	1,647
Impact of Revisions
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income (loss)		9	(22)	10	(2)	(30)	(13)	(32)		(22)	(31)	35	(56)
Foreign currency translation adjustment											0	5	(3)
Change in unrealized gains (losses), net of reclassification adjustment			(4)	165	(77)	2		(75)		90	16	3	(18)
Other comprehensive income (loss)		0	(4)	165	(77)	2	(4)	(75)		90	16	8	(21)
Comprehensive income (loss)		9	(26)	175	(79)	(28)	(17)	(107)		68	(15)	43	(77)
Comprehensive income (loss) attributable to Holdings		$ 9	$ (26)	$ 175	$ (79)	$ (28)	$ (17)	$ (107)		$ 68	$ (15)	$ 43	$ (77)