Newly Adopted Accounting Standards and Accounting Standards Not Yet Implemented Accounting Standards Not Yet Implemented (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Deferred Financing Costs [Line Items]
Other current assets	$ 493.9	$ 486.6
Investments and other assets	976.4	910.4
Total assets	12,836.5	11,777.7
Current portion of long-term debt	18.2	20.2
Long-term debt, less current portion	950.5	0.0
Total liabilities	$ 12,504.6	$ 11,596.2