Basis of Presentation - Credit loss adoption (Detail) - USD ($) $ in Millions		3 Months Ended
	Jan. 01, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained Earnings (Accumulated Deficit)		$ 10,718	$ 10,592
Adoption of new accounting standard	$ (2)	(2)
Accounts receivable, net of allowance		1,846	1,949
Allowance for doubtful accounts		$ 28	$ 28	$ 30	$ 29
Receivables outstanding less than 60 days (as a percent)		90.00%
Threshold period to measure receivables		60 days
COVID 19 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Allowance for doubtful accounts		$ 5
Accounting Standards Update 2016-13 [Member] | Adjustment [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Allowance for doubtful accounts	$ (1)	$ (1)