INCOME TAXES - Deferred Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Credit loss deduction	$ 3,809	$ 3,419
Deferred compensation and employee benefits	2,224	1,975
Repositioning and settlement reserves	345	428
U.S. tax on non-U.S. earnings	1,030	2,080
Investment and loan basis differences	2,727	4,891
Tax credit and net operating loss carry-forwards	19,711	20,759
Fixed assets and leases	2,607	1,006
Other deferred tax assets	2,996	2,385
Gross deferred tax assets	35,449	36,943
Valuation allowance	6,476	9,258
Deferred tax assets after valuation allowance	28,973	27,685
Deferred tax liabilities
Intangibles and leases	(2,640)	(1,284)
Debt issuances	(201)	(530)
Non-U.S. withholding taxes	(974)	(1,040)
Interest-related items	(587)	(594)
Other deferred tax liabilities	(1,477)	(1,334)
Gross deferred tax liabilities	(5,879)	(4,782)
Net deferred tax assets	$ 23,094	$ 22,903