Receivables - Additional Information (Detail)		12 Months Ended			69 Months Ended
	Mar. 30, 2012 USD ($)	Dec. 31, 2017 USD ($) financial_institution	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)
Schedule Of Financial Receivables [Line Items]
Number of arrangement with different financial institution to sell customer receivables | financial_institution		3
Funding of customer receivables sold		$ 0	$ 100,000,000
Sale of customer receivables	$ 304,000,000
Cash received for receivables	50,000,000
Deferred purchase price receivable	$ 254,000,000	187,000,000	83,000,000
Net cash funding received during the period		300,000,000
Amount of cash draws under arrangement during the period		2,358,000,000
Amount of cash repayments under arrangement during the period		(2,058,000,000)		$ 0
Amount of cash draws under arrangement since inception		600,000,000	500,000,000
Amount of cash repayments under arrangement since inception		(600,000,000)	(400,000,000)
Gross cash outflows from deferred purchased receivables		5,471,000,000	(5,367,000,000)		$ 35,409,000,000
Gross cash inflows from deferred purchased receivables		5,340,000,000	$ (5,406,000,000)
Cash collections of other receivables					$ (34,872,000,000)
Minimum
Schedule Of Financial Receivables [Line Items]
Funding of customer receivables sold		200,000,000
Maximum
Schedule Of Financial Receivables [Line Items]
Funding of customer receivables sold		$ 400,000,000