Derivative Instruments Derivative Assets and Liabilities (Details) $ in Millions		Mar. 31, 2017 USD ($) bbl rins	Dec. 31, 2016 USD ($) bbl rins
Derivatives, Fair Value [Line Items]
Assets		$ 28.5	$ 53.1
Liabilities		(74.0)	(104.4)
Counterparty netting and cash collateral, Assets	[1]	25.0	46.3
Counterparty netting and cash collateral, Liabilities	[1]	(33.9)	(61.0)
Total net fair value of derivative assets		3.5	6.8
Total net fair value of derivative liabilities		(40.1)	(43.4)
Footnote [Abstract]
Cash collateral		$ 8.9	$ 14.7
OTC commodity swaps
Footnote [Abstract]
Derivative open contract (barrels) | bbl		24,019,000	9,348,000
RIN Commitment Contracts [Member]
Footnote [Abstract]
Derivative open contract (barrels) | rins		252,670,299	36,750,000
Not Designated as Hedging Instrument [Member] | OTC commodity swaps | Other current assets
Derivatives, Fair Value [Line Items]
Assets	[2]	$ 13.7	$ 37.4
Liabilities	[2]	(11.7)	(30.6)
Not Designated as Hedging Instrument [Member] | OTC commodity swaps | Other current liabilities
Derivatives, Fair Value [Line Items]
Assets	[2]	9.3	14.4
Liabilities	[2]	(16.6)	(35.2)
Not Designated as Hedging Instrument [Member] | OTC commodity swaps | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Assets	[2]	1.3	0.0
Liabilities	[2]	(1.2)	0.0
Not Designated as Hedging Instrument [Member] | OTC commodity swaps | Other long term liabilities
Derivatives, Fair Value [Line Items]
Assets	[2]	2.3	0.0
Liabilities	[2]	(2.7)	0.0
Not Designated as Hedging Instrument [Member] | RIN Commitment Contracts [Member] | Other current liabilities
Derivatives, Fair Value [Line Items]
Assets	[3]	0.0	0.0
Liabilities	[3]	$ (3.4)	$ (0.8)
Designated as Hedging Instrument [Member] | OTC commodity swaps
Footnote [Abstract]
Derivative open contract (barrels) | bbl		1,968,000	3,392,000
Designated as Hedging Instrument [Member] | OTC commodity swaps | Other current assets
Derivatives, Fair Value [Line Items]
Assets	[2]	$ 1.4	$ 0.1
Liabilities	[2]	(1.0)	(2.5)
Designated as Hedging Instrument [Member] | OTC commodity swaps | Other current liabilities
Derivatives, Fair Value [Line Items]
Assets	[2]	0.5	1.2
Liabilities	[2]	(14.8)	(18.0)
Designated as Hedging Instrument [Member] | OTC commodity swaps | Other long term liabilities
Derivatives, Fair Value [Line Items]
Assets	[2]	0.0	0.0
Liabilities	[2]	$ (22.6)	$ (17.3)

[1] As of March 31, 2017 and December 31, 2016, $8.9 million and $14.7 million, respectively, of cash collateral held by counterparties has been netted with the derivatives with each counterparty.

[2] ) As of March 31, 2017 and December 31, 2016, we had open derivative positions representing 24,019,000 barrels and 9,348,000 barrels, respectively, of crude oil and refined petroleum products. Of these open positions, contracts representing 1,968,000 barrels and 3,392,000 barrels were designated as cash flow hedging instruments as of March 31, 2017 and December 31, 2016, respectively.

[3] As of March 31, 2017 and December 31, 2016, we had open RIN contracts representing 252,670,299 and 36,750,000 RINs, respectively.