FAIR VALUE MEASUREMENTS - Schedule of Financial Instruments not Recorded at Fair Value (Details) - USD ($) $ in Millions		Dec. 31, 2025	Dec. 31, 2024
Financial assets:
Debt securities held to maturity	[1]	$ 7,933	$ 8,599
Debt securities held-to-maturity, fair value		7,150	7,540
Loans held for sale		133	33
Loans held for sale, fair value		133	33
Net loans and leases	[2]	140,749	137,142
Net loans and leases, fair value		140,131	136,293
Other assets		807	710
Other assets, fair value		807	710
Financial liabilities:
Deposits		183,313	174,776
Deposits, fair value		183,277	174,651
Short-term borrowed funds		6
Short-term borrowed funds, fair value		6
Long-term borrowed funds	[2]	11,224	12,401
Long-term borrowed funds, fair value		11,472	12,247
Off-balance-sheet risks, amount, asset		13,600	11,200
Level 1
Financial assets:
Debt securities held to maturity		0	0
Debt securities held-to-maturity, fair value		0	0
Loans held for sale		0	0
Loans held for sale, fair value		0	0
Net loans and leases		0	0
Net loans and leases, fair value		0	0
Other assets		0	0
Other assets, fair value		0	0
Financial liabilities:
Deposits		0	0
Deposits, fair value		0	0
Short-term borrowed funds		0
Short-term borrowed funds, fair value		0
Long-term borrowed funds		0	0
Long-term borrowed funds, fair value		0	0
Level 2
Financial assets:
Debt securities held to maturity		7,595	8,187
Debt securities held-to-maturity, fair value		6,812	7,136
Loans held for sale		0	0
Loans held for sale, fair value		0	0
Net loans and leases		437	979
Net loans and leases, fair value		437	979
Other assets		768	689
Other assets, fair value		768	689
Financial liabilities:
Deposits		183,313	174,776
Deposits, fair value		183,277	174,651
Short-term borrowed funds		6
Short-term borrowed funds, fair value		6
Long-term borrowed funds		11,224	12,401
Long-term borrowed funds, fair value		11,472	12,247
Level 3
Financial assets:
Debt securities held to maturity		338	412
Debt securities held-to-maturity, fair value		338	404
Loans held for sale		133	33
Loans held for sale, fair value		133	33
Net loans and leases		140,312	136,163
Net loans and leases, fair value		139,694	135,314
Other assets		39	21
Other assets, fair value		39	21
Financial liabilities:
Deposits		0	0
Deposits, fair value		0	0
Short-term borrowed funds		0
Short-term borrowed funds, fair value		0
Long-term borrowed funds		0	0
Long-term borrowed funds, fair value		$ 0	$ 0

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

[2] Includes amounts in consolidated VIEs. See Note 9 for additional information.