FAIR VALUE MEASUREMENTS - Defined benefit plan assets (Details) - Fair Value, Recurring - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
United States
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	$ 187	$ 176
United States | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	20	23
United States | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	167	153
United States | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	81	88
United States | Fixed income securities | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	81	88
United States | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	64	59
United States | Equity securities | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	64	51
United States | Alternative credit fund
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	22
United States | Alternative credit fund | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	22
United States | Cash
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	20
United States | Cash | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Real estate and other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		29
United States | Real estate and other | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		14
United States | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	8
United States | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
United States | Valuation, Market Approach | Alternative credit fund | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Valuation, Market Approach | Alternative credit fund | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Valuation, Market Approach | Alternative credit fund | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Valuation, Market Approach | Cash | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	20
United States | Valuation, Market Approach | Cash | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Valuation, Market Approach | Cash | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
United States | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		15
United States | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		0
United States | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		0
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	2,041	505
Non-U.S. | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	181	111
Non-U.S. | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
Non-U.S. | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	199	110
Non-U.S. | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	1,661	284
Non-U.S. | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	1,123	168
Non-U.S. | Fixed income securities | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	1,072	168
Non-U.S. | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	283	185
Non-U.S. | Equity securities | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	283	74
Non-U.S. | Cash
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	130
Non-U.S. | Insurance contract and other (a)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	113	152
Non-U.S. | Insurance contract and other (a) | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		42
Non-U.S. | Real estate and other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	392
Non-U.S. | Real estate and other | Fair Value Measured at Net asset value (NAV)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	306
Non-U.S. | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	51	0
Non-U.S. | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
Non-U.S. | Valuation, Market Approach | Fixed income securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		0
Non-U.S. | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	111
Non-U.S. | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
Non-U.S. | Valuation, Market Approach | Equity securities | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount		0
Non-U.S. | Valuation, Market Approach | Cash | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	130
Non-U.S. | Valuation, Market Approach | Cash | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
Non-U.S. | Valuation, Market Approach | Insurance contract and other (a) | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
Non-U.S. | Valuation, Market Approach | Insurance contract and other (a) | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0	0
Non-U.S. | Valuation, Market Approach | Insurance contract and other (a) | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	113	$ 110
Non-U.S. | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
Non-U.S. | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	0
Non-U.S. | Valuation, Market Approach | Real estate and other | Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan Assets, amount	$ 86