Basis of Presentation - Additional Information (Detail) (USD $) In Millions	Sep. 30, 2011
Convertible Notes 1 Point 75 Percent Due 2011
Convertible senior notes included in calculation of net income per share	$ 1,701
Convertible Notes 1 Point 75 Percent Due 2013
Convertible senior notes included in calculation of net income per share	$ 1,724

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

Name:	us-gaap_SeniorNotes
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant