INVESTMENTS - Fair Value of AFS Securities (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair value
Less than 12 months	$ 79,670	$ 82,905
12 months or longer	27,540	33,848
Total	107,210	116,753
Gross unrealized losses
Less than 12 months	555	1,037
12 months or longer	1,044	1,495
Total	1,599	2,532
Commercial and other
Fair value
Less than 12 months	0	0
12 months or longer	1	1
Total	1	1
Gross unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
U.S. government-sponsored agency guaranteed
Fair value
Less than 12 months	17,579	16,690
12 months or longer	9,345	8,484
Total	26,924	25,174
Gross unrealized losses
Less than 12 months	219	255
12 months or longer	544	687
Total	763	942
Residential
Fair value
Less than 12 months	31	375
12 months or longer	481	216
Total	512	591
Gross unrealized losses
Less than 12 months	0	1
12 months or longer	1	1
Total	1	2
Mortgage-backed securities
Fair value
Less than 12 months	17,610	17,065
12 months or longer	9,827	8,701
Total	27,437	25,766
Gross unrealized losses
Less than 12 months	219	256
12 months or longer	545	688
Total	764	944
U.S. Treasury
Fair value
Less than 12 months	14,391	13,660
12 months or longer	1,507	1,710
Total	15,898	15,370
Gross unrealized losses
Less than 12 months	58	166
12 months or longer	56	98
Total	114	264
U.S. Treasury and federal agency securities
Fair value
Less than 12 months	14,391	13,660
12 months or longer	1,507	1,710
Total	15,898	15,370
Gross unrealized losses
Less than 12 months	58	166
12 months or longer	56	98
Total	114	264
State and municipal
Fair value
Less than 12 months	644	855
12 months or longer	582	335
Total	1,226	1,190
Gross unrealized losses
Less than 12 months	25	72
12 months or longer	48	31
Total	73	103
Foreign government
Fair value
Less than 12 months	45,850	49,384
12 months or longer	13,947	19,719
Total	59,797	69,103
Gross unrealized losses
Less than 12 months	223	487
12 months or longer	353	600
Total	576	1,087
Corporate
Fair value
Less than 12 months	416	455
12 months or longer	1,557	2,444
Total	1,973	2,899
Gross unrealized losses
Less than 12 months	28	45
12 months or longer	42	77
Total	70	122
Asset-backed securities
Fair value
Less than 12 months	299	388
12 months or longer	0	0
Total	299	388
Gross unrealized losses
Less than 12 months	2	11
12 months or longer	0	0
Total	2	11
Other debt securities
Fair value
Less than 12 months	460	1,098
12 months or longer	120	939
Total	580	2,037
Gross unrealized losses
Less than 12 months	0	0
12 months or longer	0	1
Total	$ 0	$ 1