FAIR VALUE MEASUREMENTS - Schedule of Financial Instruments not Recorded at Fair Value (Details) - USD ($) $ in Millions		Sep. 30, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset-backed investments included in HTM securities	[1]	$ 10,071	$ 2,242
Debt Securities held-to-maturity, fair value		9,373	2,289
Other loans held for sale, carrying value		914	735
Other loans held for sale, fair value		909	735
Loans and leases, carrying value		156,140	128,163
Loans and leases, fair value		150,566	128,156
Other assets, carrying value		1,113	624
Other assets, fair value		1,113	624
Deposits, carrying value		178,566	154,361
Deposits, fair value		178,417	154,366
Short-term borrowed funds, carrying value		263	74
Short-term borrowed funds, fair value		263	74
Long-term borrowed funds, carrying value		16,286	6,932
Long-term borrowed funds, fair value		15,786	7,188
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset-backed investments included in HTM securities		0	0
Debt Securities held-to-maturity, fair value		0	0
Other loans held for sale, carrying value		0	0
Other loans held for sale, fair value		0	0
Loans and leases, carrying value		0	0
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, carrying value		0	0
Short-term borrowed funds, fair value		0	0
Long-term borrowed funds, carrying value		0	0
Long-term borrowed funds, fair value		0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset-backed investments included in HTM securities		9,457	1,505
Debt Securities held-to-maturity, fair value		8,804	1,557
Other loans held for sale, carrying value		0	0
Other loans held for sale, fair value		0	0
Loans and leases, carrying value		555	645
Loans and leases, fair value		555	645
Other assets, carrying value		1,098	609
Other assets, fair value		1,098	609
Deposits, carrying value		178,566	154,361
Deposits, fair value		178,417	154,366
Short-term borrowed funds, carrying value		263	74
Short-term borrowed funds, fair value		263	74
Long-term borrowed funds, carrying value		16,286	6,932
Long-term borrowed funds, fair value		15,786	7,188
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset-backed investments included in HTM securities		614	737
Debt Securities held-to-maturity, fair value		569	732
Other loans held for sale, carrying value		914	735
Other loans held for sale, fair value		909	735
Loans and leases, carrying value		155,585	127,518
Loans and leases, fair value		150,011	127,511
Other assets, carrying value		15	15
Other assets, fair value		15	15
Deposits, carrying value		0	0
Deposits, fair value		0	0
Short-term borrowed funds, carrying value		0	0
Short-term borrowed funds, fair value		0	0
Long-term borrowed funds, carrying value		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.