SECURITIES - Schedule of Investments (Details) - USD ($) $ in Millions		Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Fair Value	[1]	$ 35,697	$ 32,765
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	[1]	7,933	8,599
Gross Unrealized Gains		2	1
Gross Unrealized Losses		(785)	(1,060)
Fair Value		7,150	7,540
Total equity securities, at cost, Amortized Cost		807	710
Equity securities, at cost, Fair Value		807	710
Equity securities, Amortized Cost		317	220
Equity securities, Fair Value		317	220
Portfolio level basis adjustments excluded from amortized cost		17	(75)
Debt Securities
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		36,900	34,986
Gross Unrealized Gains		225	36
Gross Unrealized Losses		(1,428)	(2,257)
Fair Value		35,697	32,765
U.S. Treasury and other
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		3,163	3,631
Gross Unrealized Gains		10	3
Gross Unrealized Losses		(50)	(109)
Fair Value		3,123	3,525
State and political subdivisions
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		1	1
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Fair Value		1	1
Mortgage-backed securities
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		33,647	31,170
Gross Unrealized Gains		215	33
Gross Unrealized Losses		(1,378)	(2,148)
Fair Value		32,484	29,055
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		7,595	8,187
Gross Unrealized Gains		2	0
Gross Unrealized Losses		(785)	(1,051)
Fair Value		6,812	7,136
Federal agencies and U.S. government sponsored entities
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		33,379	30,897
Gross Unrealized Gains		215	33
Gross Unrealized Losses		(1,374)	(2,135)
Fair Value		32,220	28,795
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		7,595	8,187
Gross Unrealized Gains		2	0
Gross Unrealized Losses		(785)	(1,051)
Fair Value		6,812	7,136
Other/non-agency
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		268	273
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(4)	(13)
Fair Value		264	260
Collateralized loan obligations
Debt Securities, Available-for-Sale, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		89	184
Gross Unrealized Gains		0	0
Gross Unrealized Losses		0	0
Fair Value		89	184
Asset-backed securities
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost		338	412
Gross Unrealized Gains		0	1
Gross Unrealized Losses		0	(9)
Fair Value		$ 338	$ 404

[1] Includes only collateral pledged by the Company where counterparties have the right to sell or pledge the collateral.