Derivative Instruments And Hedging Activities - Fair Value of Derivative Instruments (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Assets	$ 66	$ 88
Liabilities	1,594	1,716
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Assets	63	57
Liabilities	86	184
Designated as Hedging Instrument | Long-term debt | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	1,482	1,530
Designated as Hedging Instrument | Cross-currency swap | Other assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Assets	7	0
Designated as Hedging Instrument | Cross-currency swap | Accounts payable and accrued liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	0	23
Designated as Hedging Instrument | Cross-currency swap | Other liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	80	144
Designated as Hedging Instrument | Interest Rate Swap | Other assets | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Assets	37	57
Designated as Hedging Instrument | Interest Rate Swap | Other liabilities | Fair Value Hedging
Derivatives, Fair Value [Line Items]
Liabilities	5	1
Designated as Hedging Instrument | FX forwards | Other current assets | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Assets	19	0
Designated as Hedging Instrument | FX forwards | Accounts payable and accrued liabilities | Net Investment Hedging
Derivatives, Fair Value [Line Items]
Liabilities	1	16
Not Designated as Accounting Hedges | FX forwards | Other current assets
Derivatives, Fair Value [Line Items]
Assets	3	31
Not Designated as Accounting Hedges | FX forwards | Accounts payable and accrued liabilities
Derivatives, Fair Value [Line Items]
Liabilities	$ 26	$ 2