Other Balance Sheet Accounts (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Other Current Liabilities
Environmental contingencies	$ 26.8	$ 32.5
Deferred revenue	21.2	27.2
Accrued compensation	39.0	49.6
Accrued interest	17.0	16.2
Pension liabilities included in other current liabilities	15.0	14.4
Income taxes payable	8.5	5.7
Other accrued liabilities	56.1	63.3
Total Other Current Liabilities	183.6	208.9
Other Liabilities, Noncurrent [Abstract]
Environmental contingencies	41.5	33.8
Liability to unconsolidated affiliate	27.4	27.0
Asset Retirement Obligation	8.7	10.2
Postemployment liability	7.0	7.2
Deferred revenue	9.4	2.3
Other noncurrent liabilities	59.6	46.2
Other Liabilities, Noncurrent	$ 153.6	$ 126.7