Financial Instruments - Balance Sheet (Details) - Foreign currency - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivatives designated as hedging instruments Under 815: | Prepayments and other current assets
Derivatives, Fair Value
Derivative assets	$ 1	$ 0
Derivatives designated as hedging instruments Under 815: | Accounts payable and accrued expenses
Derivatives, Fair Value
Derivative liability	2	1
Derivatives designated as hedging instruments Under 815: | Other non-current assets | Net investment hedge
Derivatives, Fair Value
Derivative assets	23	3
Derivatives designated as hedging instruments Under 815: | Other non-current liabilities | Net investment hedge
Derivatives, Fair Value
Derivative liability	11	8
Derivatives not designated as hedging instruments | Prepayments and other current assets
Derivatives, Fair Value
Derivative assets	1	0
Derivatives not designated as hedging instruments | Accounts payable and accrued expenses
Derivatives, Fair Value
Derivative liability	$ 0	$ 0