Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on commodity contracts	$ 7.9	$ 1.0
Assets
Total assets	38.9		$ 14.5
Liabilities
Cash collateral	7.0		38.8
Fair Value, Measurements, Recurring
Assets
Total assets	2,609.1		269.8
Liabilities
Total liabilities	(2,875.3)		(760.7)
Net assets (liabilities)	(266.2)		(490.9)
Fair Value, Measurements, Recurring | Commodity contracts
Assets
Total assets	2,591.2		240.3
Liabilities
Total liabilities	(2,546.0)		(263.0)
Fair Value, Measurements, Recurring | Commodities Investment
Assets
Total assets	4.6		12.1
Fair Value, Measurements, Recurring | RIN commitment contracts
Assets
Total assets	2.2		0.6
Liabilities
Total liabilities	(1.7)		(1.9)
Fair Value, Measurements, Recurring | Environmental Credits Obligation
Assets
Total assets	11.1		16.8
Liabilities
Total liabilities	(50.2)		(18.5)
Fair Value, Measurements, Recurring | J. Aron supply and offtake obligations
Liabilities
Total liabilities	(277.4)		(477.3)
Fair Value, Measurements, Recurring | Level 1
Assets
Total assets	4.6		12.1
Liabilities
Total liabilities	0.0		0.0
Net assets (liabilities)	4.6		12.1
Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | Commodities Investment
Assets
Total assets	4.6		12.1
Fair Value, Measurements, Recurring | Level 1 | RIN commitment contracts
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | Environmental Credits Obligation
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 2
Assets
Total assets	2,604.5		257.7
Liabilities
Total liabilities	(2,875.3)		(760.7)
Net assets (liabilities)	(270.8)		(503.0)
Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Assets
Total assets	2,591.2		240.3
Liabilities
Total liabilities	(2,546.0)		(263.0)
Fair Value, Measurements, Recurring | Level 2 | Commodities Investment
Assets
Total assets	0.0		0.0
Fair Value, Measurements, Recurring | Level 2 | RIN commitment contracts
Assets
Total assets	2.2		0.6
Liabilities
Total liabilities	(1.7)		(1.9)
Fair Value, Measurements, Recurring | Level 2 | Environmental Credits Obligation
Assets
Total assets			16.8
Liabilities
Total liabilities	(50.2)		(18.5)
Fair Value, Measurements, Recurring | Level 2 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	277.4		(477.3)
Fair Value, Measurements, Recurring | Level 3
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Net assets (liabilities)	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Commodities Investment
Assets
Total assets	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | RIN commitment contracts
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Environmental Credits Obligation
Assets
Total assets	0.0		0.0
Liabilities
Total liabilities	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	0.0		$ 0.0
Other current assets | Fair Value, Measurements, Recurring | Level 2 | Environmental Credits Obligation
Assets
Total assets	$ 11.1