Derivative Instruments And Hedging Activities - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Assets	$ 88	$ 92
Liabilities	1,716	1,403
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Assets	57	83
Liabilities	184	0
Designated as Hedging Instrument | Long-term debt | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	1,530	1,403
Designated as Hedging Instrument | Cross currency swaps | Other assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Assets	0	56
Designated as Hedging Instrument | Cross currency swaps | Accounts payable and accrued liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	23	0
Designated as Hedging Instrument | Cross currency swaps | Other liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	144	0
Designated as Hedging Instrument | Interest Rate Swap | Other assets | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Assets	57	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 | Accounts payable and accrued liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	16	0
Not Designated as Accounting Hedges | FX forwards | Other current assets
Derivatives, Fair Value [Line Items]
Assets	31	9
Not Designated as Accounting Hedges | FX forwards | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Liabilities	$ 2	$ 0