FAIR VALUE - Schedule of Carrying Values and Estimated Fair Values for Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financial Assets
Investment in marketable equity securities	$ 101	$ 84
Investment securities available for sale	33,750	19,936
Investment securities held to maturity	10,239	9,979
Fair value of derivative financial instruments	660	640
Financial Liabilities
Fair value of derivative financial instruments	625	636
Carrying Value
Financial Assets
Cash and due from banks	814	908
Interest-earning deposits at banks	21,364	33,609
Securities purchased under agreements to resell	158	473
Investment in marketable equity securities	101	84
Investment securities available for sale	33,750	19,936
Investment securities held to maturity	10,239	9,979
Loans held for sale	82	73
Net loans	136,567	129,545
Accrued interest receivable	902	832
Federal Home Loan Bank stock	20	20
Mortgage servicing rights	27	25
Financial Liabilities
Deposits with no stated maturity	141,976	129,427
Time deposits	13,253	16,427
Credit balances of factoring clients	1,016	1,089
Securities sold under customer repurchase agreements	367	485
Long-term borrowings	36,669	37,160
Accrued interest payable	134	137
Carrying Value | Qualifying Hedges
Financial Assets
Fair value of derivative financial instruments	1	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Carrying Value | Non-qualifying Hedges
Financial Assets
Fair value of derivative financial instruments	659	640
Financial Liabilities
Fair value of derivative financial instruments	625	636
Estimated Fair Value
Financial Assets
Cash and due from banks	814	908
Interest-earning deposits at banks	21,364	33,609
Securities purchased under agreements to resell	158	473
Investment in marketable equity securities	101	84
Investment securities available for sale	33,750	19,936
Investment securities held to maturity	8,702	8,503
Loans held for sale	82	73
Net loans	134,872	126,696
Accrued interest receivable	902	832
Federal Home Loan Bank stock	20	20
Mortgage servicing rights	47	42
Financial Liabilities
Deposits with no stated maturity	141,976	129,427
Time deposits	13,247	16,416
Credit balances of factoring clients	1,016	1,089
Securities sold under customer repurchase agreements	367	485
Long-term borrowings	36,220	36,816
Accrued interest payable	134	137
Estimated Fair Value | Level 1
Financial Assets
Cash and due from banks	814	908
Interest-earning deposits at banks	21,364	33,609
Securities purchased under agreements to resell	0	0
Investment in marketable equity securities	48	36
Investment securities available for sale	0	0
Investment securities held to maturity	0	0
Loans held for sale	0	0
Net loans	0	0
Accrued interest receivable	0	0
Federal Home Loan Bank stock	0	0
Mortgage servicing rights	0	0
Financial Liabilities
Deposits with no stated maturity	0	0
Time deposits	0	0
Credit balances of factoring clients	0	0
Securities sold under customer repurchase agreements	0	0
Long-term borrowings	0	0
Accrued interest payable	0	0
Estimated Fair Value | Level 2
Financial Assets
Cash and due from banks	0	0
Interest-earning deposits at banks	0	0
Securities purchased under agreements to resell	158	473
Investment in marketable equity securities	53	48
Investment securities available for sale	33,582	19,779
Investment securities held to maturity	8,702	8,503
Loans held for sale	55	38
Net loans	1,463	1,479
Accrued interest receivable	902	832
Federal Home Loan Bank stock	20	20
Mortgage servicing rights	0	0
Financial Liabilities
Deposits with no stated maturity	141,976	129,427
Time deposits	13,247	16,416
Credit balances of factoring clients	0	0
Securities sold under customer repurchase agreements	367	485
Long-term borrowings	36,220	36,816
Accrued interest payable	134	137
Estimated Fair Value | Level 3
Financial Assets
Cash and due from banks	0	0
Interest-earning deposits at banks	0	0
Securities purchased under agreements to resell	0	0
Investment in marketable equity securities	0	0
Investment securities available for sale	168	157
Investment securities held to maturity	0	0
Loans held for sale	27	35
Net loans	133,409	125,217
Accrued interest receivable	0	0
Federal Home Loan Bank stock	0	0
Mortgage servicing rights	47	42
Financial Liabilities
Deposits with no stated maturity	0	0
Time deposits	0	0
Credit balances of factoring clients	1,016	1,089
Securities sold under customer repurchase agreements	0	0
Long-term borrowings	0	0
Accrued interest payable	0	0
Estimated Fair Value | Qualifying Hedges
Financial Assets
Fair value of derivative financial instruments	1	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Estimated Fair Value | Qualifying Hedges | Level 1
Financial Assets
Fair value of derivative financial instruments	0	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Estimated Fair Value | Qualifying Hedges | Level 2
Financial Assets
Fair value of derivative financial instruments	1	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Estimated Fair Value | Qualifying Hedges | Level 3
Financial Assets
Fair value of derivative financial instruments	0	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Estimated Fair Value | Non-qualifying Hedges
Financial Assets
Fair value of derivative financial instruments	659	640
Financial Liabilities
Fair value of derivative financial instruments	625	636
Estimated Fair Value | Non-qualifying Hedges | Level 1
Financial Assets
Fair value of derivative financial instruments	0	0
Financial Liabilities
Fair value of derivative financial instruments	0	0
Estimated Fair Value | Non-qualifying Hedges | Level 2
Financial Assets
Fair value of derivative financial instruments	642	633
Financial Liabilities
Fair value of derivative financial instruments	624	635
Estimated Fair Value | Non-qualifying Hedges | Level 3
Financial Assets
Fair value of derivative financial instruments	17	7
Financial Liabilities
Fair value of derivative financial instruments	$ 1	$ 1