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INVESTMENTS - Debt Securities Held-to-Maturity (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Held-to-maturity (HTM) debt securities
Amortized cost, net	$ 178,503	$ 189,831
Gross unrealized gains	81	156
Gross unrealized losses	10,727	10,467
Fair value	167,857	179,520
Allowance for credit losses on HTM debt securities	116	146	$ 130	$ 137
Other
Held-to-maturity (HTM) debt securities
Amortized cost, net	1,349	1,288
Gross unrealized gains	19	21
Gross unrealized losses	111	115
Fair value	1,257	1,194
Mortgage-backed securities
Held-to-maturity (HTM) debt securities
Amortized cost, net	65,451	66,919
Gross unrealized gains	21	24
Gross unrealized losses	7,247	6,949
Fair value	58,225	59,994
U.S. government-sponsored agency guaranteed
Held-to-maturity (HTM) debt securities
Amortized cost, net	64,102	65,631
Gross unrealized gains	2	3
Gross unrealized losses	7,136	6,834
Fair value	56,968	58,800
U.S. treasury securities
Held-to-maturity (HTM) debt securities
Amortized cost, net	81,549	89,494
Gross unrealized gains	0	0
Gross unrealized losses	2,844	3,010
Fair value	78,705	86,484
State and municipal
Held-to-maturity (HTM) debt securities
Amortized cost, net	8,517	8,608
Gross unrealized gains	20	40
Gross unrealized losses	585	469
Fair value	7,952	8,179
Foreign government
Held-to-maturity (HTM) debt securities
Amortized cost, net	620	790
Gross unrealized gains	17	20
Gross unrealized losses	0	0
Fair value	637	810
Asset-backed securities
Held-to-maturity (HTM) debt securities
Amortized cost, net	22,366	24,020
Gross unrealized gains	23	72
Gross unrealized losses	51	39
Fair value	$ 22,338	$ 24,053