Share-Based Payments (Details 3) (USD $)	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Stock option disclosures
Cash received from option exercised	$ 51,765,000	$ 21,389,000
Stock Option Awards
Weighted average assumptions relating to the valuation of stock options
Expected life (in years)	5 years	5 years
Expected volatility (as a percent)	30.90%	48.40%
Risk-free interest rate (as a percent)	1.60%	1.30%
Dividend yield (as a percent)	0.00%	0.00%
Stock option disclosures
Weighted average fair value of the stock options issued (in dollars per share)	$ 8.78	$ 11.32
Total intrinsic value of options exercised	84,600,000
Cash received from option exercised	51,800,000
Tax benefit realized for the tax deductions of stock option exercises	31,400,000
Total unrecognized compensation costs related to unvested stock option awards	$ 14,600,000
Weighted average period for recognition of unvested awards	2 years 4 months 24 days

Unrecognized cost of unvested share-based compensation awards.

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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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Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period.

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The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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-Glossary Financing Activities

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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Weighted average expected volatility rate of share-based compensation awards.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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

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