Derivative Instruments And Hedging Activities - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Assets	$ 79	$ 92
Liabilities	1,534	1,403
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Assets	74	83
Liabilities	64	0
Designated as Hedging Instrument | Long-term debt | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	1,465	1,403
Designated as Hedging Instrument | Cross-currency swap | Other assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Assets	9	56
Designated as Hedging Instrument | Cross-currency swap | Other liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	63	0
Designated as Hedging Instrument | Interest Rate Swap | Other assets | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Assets	63	27
Designated as Hedging Instrument | Interest Rate Swap | Other liabilities | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Liabilities	1	0
Designated as Hedging Instrument | FX forwards | Other current assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Assets	2	0
Not Designated as Accounting Hedges | FX forwards | Other current assets
Derivatives, Fair Value [Line Items]
Assets	5	9
Not Designated as Accounting Hedges | FX forwards | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Liabilities	$ 5	$ 0