INVESTMENTS - Fair Value of AFS Securities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair value
Less than 12 months	$ 47,608	$ 68,298
12 months or longer	68,442	98,800
Total	116,050	167,098
Gross unrealized losses
Less than 12 months	471	861
12 months or longer	1,738	2,933
Total	2,209	3,794
U.S. government-sponsored agency guaranteed
Fair value
Less than 12 months	11,165	8,602
12 months or longer	9,121	9,734
Total	20,286	18,336
Gross unrealized losses
Less than 12 months	82	86
12 months or longer	496	648
Total	578	734
Residential
Fair value
Less than 12 months	373	352
12 months or longer	242	34
Total	615	386
Gross unrealized losses
Less than 12 months	1	1
12 months or longer	2	2
Total	3	3
Mortgage-backed securities
Fair value
Less than 12 months	11,538	8,954
12 months or longer	9,363	9,768
Total	20,901	18,722
Gross unrealized losses
Less than 12 months	83	87
12 months or longer	498	650
Total	581	737
U.S. Treasury
Fair value
Less than 12 months	11,006	11,851
12 months or longer	34,798	57,669
Total	45,804	69,520
Gross unrealized losses
Less than 12 months	66	113
12 months or longer	519	1,269
Total	585	1,382
U.S. Treasury and federal agency securities
Fair value
Less than 12 months	11,006	11,851
12 months or longer	34,798	57,669
Total	45,804	69,520
Gross unrealized losses
Less than 12 months	66	113
12 months or longer	519	1,269
Total	585	1,382
State and municipal
Fair value
Less than 12 months	692	906
12 months or longer	561	324
Total	1,253	1,230
Gross unrealized losses
Less than 12 months	41	17
12 months or longer	37	74
Total	78	91
Foreign government
Fair value
Less than 12 months	21,201	42,250
12 months or longer	21,560	29,176
Total	42,761	71,426
Gross unrealized losses
Less than 12 months	230	540
12 months or longer	602	835
Total	832	1,375
Corporate
Fair value
Less than 12 months	1,965	2,319
12 months or longer	1,599	1,619
Total	3,564	3,938
Gross unrealized losses
Less than 12 months	50	103
12 months or longer	81	105
Total	131	208
Asset-backed securities
Fair value
Less than 12 months	2	154
12 months or longer	0	16
Total	2	170
Gross unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Other debt securities
Fair value
Less than 12 months	1,204	1,864
12 months or longer	561	228
Total	1,765	2,092
Gross unrealized losses
Less than 12 months	1	1
12 months or longer	1	0
Total	$ 2	$ 1