Debt - Long-term Debt (Detail) - USD ($) $ in Millions			3 Months Ended
	Oct. 12, 2018	Oct. 09, 2018	Dec. 31, 2019	Sep. 30, 2019	Apr. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 2,988	$ 2,974
4.125% Senior Secured Notes due 2024
Debt Instrument [Line Items]
Interest rate			4.125%			4.125%
4.875% Senior Secured Notes due 2024
Debt Instrument [Line Items]
Interest rate			4.875%			4.875%
3.625% Senior Secured Notes due 2026
Debt Instrument [Line Items]
Interest rate			3.625%			3.625%
Acquisition Corp. | Senior Term Loan Facility due 2023
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 1,314	1,313
Due date of senior secured notes			2023
Acquisition Corp. | 5.000% Senior Secured Notes due 2023
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 298	298
Interest rate			5.00%
Due date of senior secured notes			2023
Acquisition Corp. | 4.125% Senior Secured Notes due 2024
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 342	336
Interest rate	4.125%	4.125%	4.125%
Due date of senior secured notes	2024		2024
Acquisition Corp. | 4.875% Senior Secured Notes due 2024
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 218	218
Interest rate		4.875%	4.875%
Due date of senior secured notes		2024	2024
Acquisition Corp. | 3.625% Senior Secured Notes due 2026
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 495	488
Interest rate		3.625%	3.625%		3.625%
Due date of senior secured notes		2026	2026
Acquisition Corp. | 5.500% Senior Notes due 2026
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 321	321
Interest rate			5.50%
Due date of senior secured notes			2026
Acquisition Corp. | Revolving Credit Facility
Debt Instrument [Line Items]
Total long-term debt, including the current portion			$ 0	$ 0