Accumulated Other Comprehensive Loss and Shareholders' Equity - Accumulated Other Comprehensive (Loss) Income Activity (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	$ (79)	$ (20)	$ 703	$ 1,240	$ 1,603	$ 2,225	$ 703	$ 2,225
Other comprehensive income (loss) before reclassifications (1)							(75)	(105)
Reclassification adjustments							(10)	(8)
Total other comprehensive income (loss), net of tax	162	131	(378)	(178)	34	31	(85)	(113)
Balance at end of period	229	(79)	(20)	838	1,240	1,603	229	838
Intra-entity foreign currency long-term-investment gains							21	20
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period			(368)			(403)	(368)	(403)
Other comprehensive income (loss) before reclassifications (1)							(87)	(111)
Reclassification adjustments							0	0
Total other comprehensive income (loss), net of tax							(87)	(111)
Balance at end of period	(455)			(514)			(455)	(514)
Derivative Instrument and Other Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period			7			12	7	12
Other comprehensive income (loss) before reclassifications (1)							12	6
Reclassification adjustments							(10)	(8)
Total other comprehensive income (loss), net of tax							2	(2)
Balance at end of period	9			10			9	10
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(608)	(739)	(361)	(326)	(360)	(391)	(361)	(391)
Total other comprehensive income (loss), net of tax	162	131	(378)	(178)	34	31
Balance at end of period	$ (446)	$ (608)	$ (739)	$ (504)	$ (326)	$ (360)	$ (446)	$ (504)