Derivative Instruments and Hedging Activities - Classification and Fair Value Amounts of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 15	$ 21
Derivative liability, fair value	191	54
Derivative instruments designated as hedges
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	3	20
Derivative liability, fair value	182	52
Derivative instruments designated as hedges | Interest rate contracts | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	0	10
Derivative instruments designated as hedges | Interest rate contracts | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	179	52
Derivative instruments designated as hedges | Foreign exchange contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	3	10
Derivative instruments designated as hedges | Foreign exchange contracts | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	3	0
Undesignated derivative instruments | Foreign exchange contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	12	1
Undesignated derivative instruments | Foreign exchange contracts | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ 9	$ 2