Accounts Receivable - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Receivables [Abstract]
Securitized accounts receivable facility	$ 1,200,000,000
Maximum undivided ownership interest pooled accounts receivable amount sold	1,200,000,000
Short-term debt outstanding	$ 764,000,000	$ 675,000,000