Restructuring Costs - Schedule of Accrued Restructuring Costs Activity (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Reserve [Roll Forward]
Beginning balance			$ 22
Restructuring costs, net	$ 4	$ 3	14	$ 22
Payments			(21)
Ending balance	15		15
Employee severance and termination benefits
Restructuring Reserve [Roll Forward]
Beginning balance			10
Restructuring costs, net			12
Payments			(14)
Ending balance	8		8
Exited contractual commitments and other
Restructuring Reserve [Roll Forward]
Beginning balance			12
Restructuring costs, net			2
Payments			(7)
Ending balance	$ 7		$ 7