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Basis of Presentation - Credit loss (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jan. 01, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net of allowance	$ 1,927			$ 1,949
Total allowance increase (decrease)	$ 6
Receivables outstanding less than 60 days (as a percent)	90.00%
Threshold period to measure receivables	60 days
Allowance activity
Allowance for doubtful accounts, beginning balance	$ 28	$ 29
Additions charged to expense	40	27
Accounts written-off, net of recoveries	(29)	(31)
Acquisitions, divestitures and other, net	(4)	2
Allowance for doubtful accounts, ending balance	34	$ 27
Notes and other receivables, current and noncurrent	453
Allowance for notes and other receivables, current and noncurrent	$ 8
Receivables classified as current (as a percent)	65.00%
Accounting Standards Update 2016-13 [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance activity
Allowance for doubtful accounts, ending balance	$ (1)
Allowance for notes and other receivables, current and noncurrent			$ 4