INVESTMENTS - Fair Value of AFS Securities (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Fair value
Less than 12 months	$ 158,657	$ 144,333
12 months or longer	42,360	17,829
Total	201,017	162,162
Gross unrealized losses
Less than 12 months	4,381	1,895
12 months or longer	2,382	457
Total	6,763	2,352
Mortgage-backed securities - U.S. government-sponsored agency guaranteed
Fair value
Less than 12 months	10,219	17,039
12 months or longer	1,048	698
Total	11,267	17,737
Gross unrealized losses
Less than 12 months	387	270
12 months or longer	105	31
Total	492	301
Mortgage-backed securities - Non-U.S. residential
Fair value
Less than 12 months	197	96
12 months or longer	0	1
Total	197	97
Gross unrealized losses
Less than 12 months	3	1
12 months or longer	0	0
Total	3	1
Commercial
Fair value
Less than 12 months	6	0
12 months or longer	1	0
Total	7	0
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	10,422	17,135
12 months or longer	1,049	699
Total	11,471	17,834
Gross unrealized losses
Less than 12 months	390	271
12 months or longer	105	31
Total	495	302
U.S. Treasury
Fair value
Less than 12 months	53,236	56,448
12 months or longer	29,263	6,310
Total	82,499	62,758
Gross unrealized losses
Less than 12 months	1,322	713
12 months or longer	1,596	131
Total	2,918	844
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		56,448
12 months or longer		6,310
Total		62,758
Gross unrealized losses
Less than 12 months		713
12 months or longer		131
Total		844
State and municipal
Fair value
Less than 12 months	842	229
12 months or longer	1,037	874
Total	1,879	1,103
Gross unrealized losses
Less than 12 months	53	3
12 months or longer	148	98
Total	201	101
Foreign government
Fair value
Less than 12 months	85,907	64,319
12 months or longer	10,757	9,924
Total	96,664	74,243
Gross unrealized losses
Less than 12 months	2,407	826
12 months or longer	515	197
Total	2,922	1,023
Corporate
Fair value
Less than 12 months	4,601	2,655
12 months or longer	254	22
Total	4,855	2,677
Gross unrealized losses
Less than 12 months	196	77
12 months or longer	18	0
Total	214	77
Asset-backed securities
Fair value
Less than 12 months	174	108
12 months or longer	0	0
Total	174	108
Gross unrealized losses
Less than 12 months	1	1
12 months or longer	0	0
Total	1	1
Other debt securities
Fair value
Less than 12 months	3,475	3,439
12 months or longer	0	0
Total	3,475	3,439
Gross unrealized losses
Less than 12 months	12	4
12 months or longer	0	0
Total	$ 12	$ 4