Supplementary Data Accrued Liabilities (Details) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Accrued Liabilities [Abstract] | ||
| Salaries, benefits and related expenses | $ 301.7 | $ 499.0 |
| Acquisition obligations | 91.1 | 77.5 |
| Office and related expenses | 46.7 | 46.7 |
| Interest | 17.2 | 17.3 |
| Other | 115.3 | 153.5 |
| Total accrued liabilities | $ 572.0 | $ 794.0 |