INCOME TAXES - Deferred Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Credit loss deduction	$ 6,791	$ 3,809
Deferred compensation and employee benefits	2,510	2,224
U.S. tax on non-U.S. earnings	1,195	1,030
Investment and loan basis differences	1,486	2,727
Tax credit and net operating loss carry-forwards	17,416	19,711
Fixed assets and leases	2,935	2,607
Other deferred tax assets	3,832	3,341
Gross deferred tax assets	36,165	35,449
Valuation allowance	5,177	6,476
Deferred tax assets after valuation allowance	30,988	28,973
Deferred tax liabilities
Intangibles and leases	(2,526)	(2,640)
Debt issuances	(50)	(201)
Non-U.S. withholding taxes	(921)	(974)
Interest-related items	(597)	(587)
Other deferred tax liabilities	(2,054)	(1,477)
Gross deferred tax liabilities	(6,148)	(5,879)
Net deferred tax assets	$ 24,840	$ 23,094