Derivative Instruments And Hedging Activities - Gains (Losses) Recognized in AOCI and Reclassified from AOCI on Derivatives (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 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	$ (50)
Total, Amount of Gain/(Loss) Recognized in AOCI on Derivative, net of Tax	$ 73	$ (144)	177	(178)
Net investment hedges - reclassification of gains included in net income - Net of Tax			1	0
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(1)	0	(2)	(1)
Total, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(1)	(1)	(1)	(2)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	8	10	27	40
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	72	(143)	177	(127)
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)	8	10	27	40
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	1	(1)	0	(51)
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(1)	(1)	(2)	(2)
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	2	1	18	1
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	44	(98)	98	(81)
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)	8	10	27	40
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	26	(46)	61	(47)
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	1	(1)	0	(51)
Cash Flow Hedging Relationships, Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	(1)	(1)	(2)	(2)
Gain/(Loss) Recognized in Income on Derivative (Amount Excluded from Effectiveness Testing)	$ 0	$ 0	$ 0	$ 0