VARIABLE INTEREST ENTITIES - Schedule of Variable Interest Entities (Details) - USD ($) $ in Millions		Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entity
Lending to special purpose entities included in loans and leases		$ 122,581	$ 123,090
Securities available for sale	[1]	24,583	22,942
Securities held to maturity, carrying value	[1]	2,711	3,235
LIHTC Investments
Variable Interest Entity
LIHTC investment included in other assets		1,926	1,687
LIHTC unfunded commitments included in other liabilities		974	875
Renewable Energy
Variable Interest Entity
Renewable energy investments included in other assets		448	403
Commercial and industrial | Special Purpose Entities
Variable Interest Entity
Lending to special purpose entities included in loans and leases		1,520	1,295
Asset-backed securities
Variable Interest Entity
Securities held to maturity, carrying value		824	893
Asset-backed securities | Asset-backed securities
Variable Interest Entity
Securities held to maturity, carrying value		$ 826	$ 893

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