Derivative Instruments And Hedging Activities - Gains (Losses) Recognized in AOCI and Reclassified from AOCI on Derivatives (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	$ 0	$ (14)	$ 0	$ (50)
Total, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	(28)	(87)	105	(34)
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	0	1	0
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax			(1)	(1)
Total, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0	0	0	(1)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	9	14	19	30
Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Net Investment Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	(28)	(73)	105	16
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	0	1	0
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	9	14	19	30
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	0	(14)	0	(50)
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0	0	(1)	(1)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	0	0	0	0
FX forwards | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Net Investment Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	0	0	16	0
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	0	1	0
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	0	0	0	0
Cross-currency swap | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Net Investment Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	(18)	(49)	54	17
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	0	0	0
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	9	14	19	30
Long-term debt | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Net Investment Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	(10)	(24)	35	(1)
Net investment hedges - reclassification of gains included in net income - Net of Tax	0	0	0	0
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	0	0	0	0
Interest rate contract | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	0	(14)	0	(50)
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0	0	(1)	(1)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	$ 0	$ 0	$ 0	$ 0