INVESTMENTS - Fair Value of AFS Securities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Fair value
Less than 12 months	$ 92,630	$ 138,567
12 months or longer	79,789	53,695
Total	172,419	192,262
Gross unrealized losses
Less than 12 months	2,505	3,997
12 months or longer	2,688	2,607
Total	5,193	6,604
Mortgage-backed securities - U.S. government-sponsored agency guaranteed
Fair value
Less than 12 months	2,276	7,908
12 months or longer	9,385	3,290
Total	11,661	11,198
Gross unrealized losses
Less than 12 months	73	412
12 months or longer	624	343
Total	697	755
Less than 12 months, effect of unallocated portfolio layer cumulative basis adjustments	82
12 months or longer, effect of unallocated portfolio layer cumulative basis adjustments	767
Residential mortgages
Fair value
Less than 12 months	331	158
12 months or longer	0	1
Total	331	159
Gross unrealized losses
Less than 12 months	3	3
12 months or longer	0	0
Total	3	3
Commercial
Fair value
Less than 12 months	0	1
12 months or longer	2	1
Total	2	2
Gross unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Mortgage-backed securities
Fair value
Less than 12 months	2,607	8,067
12 months or longer	9,387	3,292
Total	11,994	11,359
Gross unrealized losses
Less than 12 months	76	415
12 months or longer	624	343
Total	700	758
U.S. Treasury
Fair value
Less than 12 months	20,820	40,701
12 months or longer	48,429	34,692
Total	69,249	75,393
Gross unrealized losses
Less than 12 months	743	1,001
12 months or longer	1,287	1,491
Total	2,030	2,492
Agency obligations
Fair value
Less than 12 months		0
12 months or longer		0
Total		0
Gross unrealized losses
Less than 12 months		0
12 months or longer		0
Total		0
U.S. Treasury and federal agency securities
Fair value
Less than 12 months	20,820	40,701
12 months or longer	48,429	34,692
Total	69,249	75,393
Gross unrealized losses
Less than 12 months	743	1,001
12 months or longer	1,287	1,491
Total	2,030	2,492
State and municipal
Fair value
Less than 12 months	414	896
12 months or longer	847	707
Total	1,261	1,603
Gross unrealized losses
Less than 12 months	14	31
12 months or longer	113	128
Total	127	159
Foreign government
Fair value
Less than 12 months	63,765	82,900
12 months or longer	19,543	14,220
Total	83,308	97,120
Gross unrealized losses
Less than 12 months	1,446	2,332
12 months or longer	607	608
Total	2,053	2,940
Corporate
Fair value
Less than 12 months	2,893	3,082
12 months or longer	1,583	784
Total	4,476	3,866
Gross unrealized losses
Less than 12 months	220	209
12 months or longer	57	37
Total	277	246
Asset-backed securities
Fair value
Less than 12 months	640	708
12 months or longer	0	0
Total	640	708
Gross unrealized losses
Less than 12 months	3	4
12 months or longer	0	0
Total	3	4
Other debt securities
Fair value
Less than 12 months	1,491	2,213
12 months or longer	0	0
Total	1,491	2,213
Gross unrealized losses
Less than 12 months	3	5
12 months or longer	0	0
Total	$ 3	$ 5