Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

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-Name Accounting Standards Codification

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 2

-Subparagraph (a)(1)

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- Definition

Per share weighted average intrinsic value of equity-based compensation awards granted. Excludes stock and unit options.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

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-Topic 718

-SubTopic 10

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- Definition

Number of allocated shares held by the Employee Stock Option Plan at balance sheet date. Allocated shares are shares that have been assigned to individual participant accounts based on a known formula.

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-Topic 718

-SubTopic 40

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- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Topic 505

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

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Number of deferred equity units equivalent to one share of common stock.

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No definition available.

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Share-Based Compensation Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued and outstanding to LLC	55
Weighted-average grant date intrinsic value of share awards	$ 107.13
Total compensation of unvested awards expected to be recognized, weighted average period			4 years
Non-cash compensation expense		$ 4	$ 3	$ 4
Unrecognized compensation costs	15		15
Employee
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-cash compensation expense		3	2	3
Non Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-cash compensation expense		$ 1	$ 1	$ 1
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Held in Employee Stock Option Plan, Allocated	82.1918		82.1918
Deferred equity unit share	0.0001
Deferred Equity Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant date intrinsic value of share awards			$ 107.13
Weighted-average grant date fair value of share awards	$ 134.62		$ 134.62
Deferred Equity Units \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Held in Employee Stock Option Plan, Allocated	41.0959		41.0959
Share awards vesting period			7 years
Deferred Equity Units \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share awards vesting period			1 year
Matching Equity Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share awards vesting period			2 years
Matching Equity Units \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Held in Employee Stock Option Plan, Allocated	41.0959		41.0959