Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)
Common stock, shares issued	63.6us-gaap_CommonStockSharesIssued	63.5us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	62.9us-gaap_CommonStockSharesOutstanding	62.9us-gaap_CommonStockSharesOutstanding
Treasury stock, shares	0.7us-gaap_TreasuryStockNumberOfSharesHeld	0.6us-gaap_TreasuryStockNumberOfSharesHeld

Face amount or stated value per share of common stock.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Number of shares held for each class of treasury stock.

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