INCOME TAXES - Deferred Tax Assets Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Valuation allowance	$ 6,476	$ 9,258
Decrease in valuation allowance from increases in foreign source income	300
Decrease in valuation allowance from discrete items	200
Decrease in valuation allowance from changes in foreign source income	100
Increase in valuation allowance from prior year tax return adjustments	200
Deferred tax liability	5,879	4,782
Foreign Tax Credit Carryforwards
Valuation Allowance [Line Items]
Valuation allowance	4,600
Foreign tax credit carryforwards more-than-likely not enabled	200
U.S. Residual Deferred Tax Asset Related to Non-U.S. Branches
Valuation Allowance [Line Items]
Valuation allowance	800	1,700
Deferred tax liability	900
Local Non-U.S. Deferred Tax Assets
Valuation Allowance [Line Items]
Valuation allowance	1,000	1,500
State Net Operating Loss Carryforwards
Valuation Allowance [Line Items]
Valuation allowance	100
Foreign Tax Credit Carryforwards, Branch Basket
Valuation Allowance [Line Items]
Valuation allowance	3,500	4,400
Foreign Tax Credit Carryforwards, General Basket
Valuation Allowance [Line Items]
Valuation allowance	$ 1,100	$ 1,600