Other Long-term Liabilities - Schedule of Other Long-term Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other Liabilities Noncurrent [Line Items]
Asset retirement obligations	$ 53.0	$ 50.8
Mandatorily redeemable preferred interests	4.2	76.2
Deferred revenue	135.2	136.2
Other liabilities	23.7	24.5
Total long-term liabilities	589.1	597.9
Permian Acquisition [Member]
Other Liabilities Noncurrent [Line Items]
Permian Acquisition contingent consideration, noncurrent portion	$ 373.0	$ 310.2