FAIR VALUE MEASUREMENTS - Schedule of Financial Instruments not Recorded at Fair Value (Details) - USD ($) $ in Millions		Sep. 30, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities held to maturity, carrying value	[1]	$ 8,124	$ 8,599
Debt securities held to maturity, fair value		7,295	7,540
Loans held for sale, carrying value		566	33
Loans held for sale, fair value		566	33
Net loans and leases	[2]	138,898	137,142
Net loans and leases, fair value		138,627	136,293
Other assets, carrying value		710	710
Other assets, fair value		710	710
Deposits, carrying value		180,011	174,776
Deposits, fair value		179,967	174,651
Short-term borrowed funds		1
Short-term borrowed funds, fair value		1
Long-term borrowed funds	[2]	10,441	12,401
Long-term borrowed funds, fair value		10,649	12,247
Cash-related financial instruments not recorded at fair value in the consolidated balance sheet		12,300	11,200
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities held to maturity, carrying value		0	0
Debt securities held to maturity, fair value		0	0
Loans held for sale, carrying value		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, carrying value		0	0
Other assets, fair value		0	0
Deposits, carrying value		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
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities held to maturity, carrying value		7,767	8,187
Debt securities held to maturity, fair value		6,938	7,136
Loans held for sale, carrying value		0	0
Loans held for sale, fair value		0	0
Net loans and leases		677	979
Net loans and leases, fair value		677	979
Other assets, carrying value		689	689
Other assets, fair value		689	689
Deposits, carrying value		180,011	174,776
Deposits, fair value		179,967	174,651
Short-term borrowed funds		1
Short-term borrowed funds, fair value		1
Long-term borrowed funds		10,441	12,401
Long-term borrowed funds, fair value		10,649	12,247
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities held to maturity, carrying value		357	412
Debt securities held to maturity, fair value		357	404
Loans held for sale, carrying value		566	33
Loans held for sale, fair value		566	33
Net loans and leases		138,221	136,163
Net loans and leases, fair value		137,950	135,314
Other assets, carrying value		21	21
Other assets, fair value		21	21
Deposits, carrying value		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 6 for additional information.