Other Balance Sheet Accounts (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other Current Liabilities
Accrued compensation	$ 39.0	$ 60.7
Accrued interest	29.9	16.5
Deferred revenue	29.6	19.5
Environmental contingencies	22.4	23.5
Income taxes payable	17.9	12.2
Pension liabilities included in other current liabilities	15.3	15.0
Other accrued liabilities	79.4	70.4
Total Other Current Liabilities	233.5	217.8
Other Liabilities, Noncurrent [Abstract]
Environmental contingencies	42.6	46.8
Liability to unconsolidated affiliate	38.5	32.7
Fair value of currency and interest rate contracts	35.8	22.7
Deferred revenue	17.1	14.9
Asset Retirement Obligation	9.6	10.4
Deferred income taxes	8.3	8.2
Postemployment liability	5.0	5.2
Other noncurrent liabilities	29.0	28.4
Other Liabilities, Noncurrent	$ 185.9	$ 169.3