Commitments and Contingencies - Environmental, Health and Safety Matters (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Loss Contingencies [Line Items]
Environmental expenditures capitalized	$ 2.3	$ 2.6	$ 7.0	$ 6.1
EHS
Loss Contingencies [Line Items]
Environmental accruals	4.3		4.3		$ 4.8
EHS | CRRM
Loss Contingencies [Line Items]
Cost of renewable identification numbers expense	105.6	$ 51.0	99.2	$ 94.1
Biofuel blending obligation recorded in other current liabilities	$ 279.9		$ 279.9		$ 186.3