Accounts Receivable - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum undivided ownership interest pooled accounts receivable amount sold	$ 1,200,000,000
Short-term debt outstanding	665,000,000	$ 675,000,000
Securitization Facility [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Securitized accounts receivable facility	$ 1,200,000,000