Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||||||
| Unrecognized tax benefits, beginning of year | $ 28.6 | $ 169.9 | $ 167.2 | ||||
| Additions based on tax positions related to the current year | 25.3 | 6.0 | 18.4 | ||||
| Additions for tax positions of prior years | 7.8 | 0.4 | 9.7 | ||||
| Reductions for tax positions of prior years | (1.9) | (1.2) | (13.4) | ||||
| Lapse of statute of limitations | (3.3) | (1.3) | (5.5) | ||||
| Settlements | (0.6) | (0.6) | (1.5) | ||||
| Effect of foreign currency translation | 1.9 | ||||||
| Effect of foreign currency translation | (0.4) | (5.0) | |||||
| Separation related adjustments | 1.2 | [1] | (144.2) | [1] | 0.0 | ||
| Unrecognized tax benefits, end of year | $ 59.0 | $ 28.6 | $ 169.9 | ||||
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