The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

Equity-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			1 Months Ended		1 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Dec. 31, 2011 Stock options/rights	Jan. 31, 2012 Stock options/rights Share Grants	Dec. 31, 2011 Restricted Stock Units	Jan. 31, 2012 Restricted Stock Units Share Grants	Jan. 31, 2012 Restrict Stock With Market Performance Conditions Share Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost			$ 153		$ 539
Weighted average grant date fair values of options issued	$ 9.42	$ 10.13
Stock compensation granted, number of shares				9.8		8.6	0.5