Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Statement Of Financial Position [Abstract] | ||
| Common shares, par value | $ 0.001 | $ 0.001 |
| Common shares, shares authorized | 1,000.0 | 1,000.0 |
| Common shares, shares outstanding | 82.3 | 93.1 |
| Treasury stock shares, at cost | 5.0 |
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- Definition Face amount or stated value per share of common stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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- Definition Number of previously issued common shares repurchased by the issuing entity and held in treasury. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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