Revenue from Contracts with Customers, Contract Balances (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Contract with Customer, Asset and Liability [Abstract]
Accounts receivable, net of allowance for doubtful accounts of $19.4 and $18.7, respectively	$ 495.5	$ 536.3
Contract assets	8.1	0.0
Contract liabilities	80.7	42.7	[1]
Accounts receivable, allowance for doubtful accounts	19.4	18.7
Increase (decrease) for contract due to acquisition	$ 25.6	$ 25.6

[1] For purposes of comparability, "Advance payments on sales contracts" as of December 31, 2017 was reclassified to "Contract liabilities." See Note 12 "Revenue from Contracts with Customers" for an explanation of the Contract liabilities account included in "Accrued liabilities" in the Condensed Consolidated Balance Sheets.