Long-Term Debt (Parenthetical) (Detail)	Dec. 31, 2012 1.375% Notes Due 2018	Oct. 30, 2012 1.375% Notes Due 2018	Dec. 31, 2012 4.40% Notes Due 2021	Dec. 20, 2010 4.40% Notes Due 2021	Dec. 31, 2012 2.875% Notes Due 2016	Dec. 20, 2010 2.875% Notes Due 2016	Dec. 31, 2012 6.70% Notes Due 2026
Debt Disclosure [Line Items]
Debt instrument interest rate	1.375%	1.375%	4.40%	4.40%	2.875%	2.875%	6.70%
Debt instrument maturity date	2018	2018	2021	2021	2016	2016	2026

Interest rate stated in the contractual debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

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

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant