Accounts Receivable - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 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	$ 679,000,000us-gaap_SecuredDebtCurrent	$ 675,000,000us-gaap_SecuredDebtCurrent

Carrying value as of the balance sheet date of the portion of long-term, collateralized debt obligations due within one year or the operating cycle, if longer. Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.20)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20

-Article 5

Name:	us-gaap_SecuredDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant