Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain (loss) on commodity contracts	$ (8.9)	$ 1.0	$ (1.0)	$ 2.0
Assets
Total assets	54.5		54.5		$ 14.5
Liabilities
Cash collateral	11.5		11.5		38.8
Fair Value, Measurements, Recurring
Assets
Total assets	2,183.2		2,183.2		269.8
Liabilities
Total liabilities	(2,489.9)		(2,489.9)		(760.7)
Net assets (liabilities)	(306.7)		(306.7)		(490.9)
Fair Value, Measurements, Recurring | Commodity contracts
Assets
Total assets	2,142.4		2,142.4		240.3
Liabilities
Total liabilities	(2,115.0)		(2,115.0)		(263.0)
Fair Value, Measurements, Recurring | Commodities Investment
Assets
Total assets	1.0		1.0		12.1
Fair Value, Measurements, Recurring | Right To Receive Crude Oil Barrels [Member]
Assets
Total assets	35.7		35.7
Fair Value, Measurements, Recurring | RIN commitment contracts
Assets
Total assets	4.1		4.1		0.6
Liabilities
Total liabilities	(4.3)		(4.3)		(1.9)
Fair Value, Measurements, Recurring | Environmental Credits Obligation
Assets
Total assets					16.8
Liabilities
Total liabilities	(56.6)		(56.6)		(18.5)
Fair Value, Measurements, Recurring | J. Aron supply and offtake obligations
Liabilities
Total liabilities	(314.0)		(314.0)		(477.3)
Fair Value, Measurements, Recurring | Level 1
Assets
Total assets	1.0		1.0		12.1
Liabilities
Total liabilities	0.0		0.0		0.0
Net assets (liabilities)	1.0		1.0		12.1
Fair Value, Measurements, Recurring | Level 1 | Commodity contracts
Assets
Total assets	0.0		0.0		0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | Commodities Investment
Assets
Total assets	1.0		1.0		12.1
Fair Value, Measurements, Recurring | Level 1 | Right To Receive Crude Oil Barrels [Member]
Assets
Total assets	0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | RIN commitment contracts
Assets
Total assets	0.0		0.0		0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | Environmental Credits Obligation
Assets
Total assets					0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 1 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 2
Assets
Total assets	2,182.2		2,182.2		257.7
Liabilities
Total liabilities	(2,489.9)		(2,489.9)		(760.7)
Net assets (liabilities)	(307.7)		(307.7)		(503.0)
Fair Value, Measurements, Recurring | Level 2 | Commodity contracts
Assets
Total assets	2,142.4		2,142.4		240.3
Liabilities
Total liabilities	(2,115.0)		(2,115.0)		(263.0)
Fair Value, Measurements, Recurring | Level 2 | Commodities Investment
Assets
Total assets	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 2 | Right To Receive Crude Oil Barrels [Member]
Assets
Total assets	35.7		35.7
Fair Value, Measurements, Recurring | Level 2 | RIN commitment contracts
Assets
Total assets	4.1		4.1		0.6
Liabilities
Total liabilities	(4.3)		(4.3)		(1.9)
Fair Value, Measurements, Recurring | Level 2 | Environmental Credits Obligation
Assets
Total assets					16.8
Liabilities
Total liabilities	(56.6)		(56.6)		(18.5)
Fair Value, Measurements, Recurring | Level 2 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	314.0		314.0		(477.3)
Fair Value, Measurements, Recurring | Level 3
Assets
Total assets	0.0		0.0		0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Net assets (liabilities)	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Commodity contracts
Assets
Total assets	0.0		0.0		0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Commodities Investment
Assets
Total assets	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Right To Receive Crude Oil Barrels [Member]
Assets
Total assets	0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | RIN commitment contracts
Assets
Total assets	0.0		0.0		0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | Environmental Credits Obligation
Assets
Total assets					0.0
Liabilities
Total liabilities	0.0		0.0		0.0
Fair Value, Measurements, Recurring | Level 3 | J. Aron supply and offtake obligations
Liabilities
Total liabilities	$ 0.0		$ 0.0		$ 0.0