VARIABLE INTEREST ENTITIES - Schedule of Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions		Mar. 31, 2024	Dec. 31, 2023
ASSETS:
Cash and due from banks	[1]	$ 1,098	$ 1,794
Interest-bearing deposits in banks		392	405
Net loans and leases	[1]	141,102	143,861
Other assets	[1]	13,571	13,359
TOTAL ASSETS		220,448	221,964
LIABILITIES:
Long-term borrowed funds	[1]	13,804	13,467
Other liabilities	[1]	4,741	4,746
TOTAL LIABILITIES		196,687	197,622
Variable Interest Entity, Primary Beneficiary
ASSETS:
Cash and due from banks		0	13
Interest-bearing deposits in banks		169	106
Net loans and leases		4,039	3,194
Other assets		17	14
TOTAL ASSETS		4,225	3,327
LIABILITIES:
Long-term borrowed funds		3,530	2,692
Other liabilities		9	8
TOTAL LIABILITIES		$ 3,539	$ 2,700

[1] Includes amounts in consolidated VIEs. See Note 6 for additional information.