Receivables - Additional Information (Detail) (USD $)	1 Months Ended	9 Months Ended
	Mar. 31, 2012	Sep. 30, 2014 Agreement
Schedule Of Financial Receivables [Line Items]
Number of arrangement with different financial institution to sell customer receivables		3
Net cash funding received in current period		$ 250,000,000
Deferred purchase price receivable	254,000,000	462,000,000
Net cash funding received		210,000,000
Amount of cash draws under arrangement		848,000,000
Amount of cash repayments under arrangement		638,000,000
Accounts receivables		15,878,000,000
Cash collections		15,206,000,000
Minimum [Member]
Schedule Of Financial Receivables [Line Items]
Funding of customer receivables sold		50,000,000
Maximum [Member]
Schedule Of Financial Receivables [Line Items]
Funding of customer receivables sold		$ 500,000,000