Valuation and Qualifying Accounts - Summary of Activity for Valuation Allowances (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance, Accounts receivable allowance	$ (43)	$ (37)	$ (26)
Charged to costs and expenses, Accounts receivable allowance	(11)	(18)	(20)
Deductions, Accounts receivable allowance	11	12	9
Ending balance, Accounts receivable allowance	(43)	(43)	(37)
Beginning balance, Deferred tax assets valuation allowance	(5)	(6)	(3)
Charged to costs and expenses, Deferred tax assets valuation allowance	(4)	0	(3)
Deductions, Deferred tax assets valuation allowance	0	1	0
Ending balance, Deferred tax assets valuation allowance	$ (9)	$ (5)	$ (6)