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Share-Based Payments (Details 9) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items] |  |  |
Shares issued under ESPP | 6,200,000 |  |
2015 ESPP |  |  |
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items] |  |  |
Shares issued under ESPP | 167,000 | 190,000 | 78,000
Cash received under ESPP | $ 39.8 | $ 41.5 | $ 19.3
1995 ESPP |  |  |
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items] |  |  |
Shares issued under ESPP | 0 | 0 | 98,000
Cash received under ESPP | $ 0.0 | $ 0.0 | $ 30.0

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