Equity Method Investments Narrative (Details)			9 Months Ended	12 Months Ended
	Jul. 01, 2017 USD ($) joint_venture $ / shares shares	May 14, 2015 USD ($) $ / shares shares	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($)	Jun. 30, 2017 USD ($) $ / shares	Dec. 22, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Common stock, par or stated value per share (USD per share) | $ / shares	$ 0.01			$ 0.01	$ 0.01		$ 0.01
Payments to acquire equity method investments				$ 5,800,000	$ 61,600,000	$ 240,900,000
Equity method investment, non-cash consideration				0	0	8,800,000
Equity method investments				138,100,000	360,000,000
Impairment of equity method investment				$ 0	245,300,000	0
Alon USA Energy, Inc.
Schedule of Equity Method Investments [Line Items]
Investment owned, balance, shares (per Share) | shares		33,700,000
Equity method investment, ownership percentage		48.00%		47.00%
Noncash or part noncash acquisition, noncash financial or equity instrument consideration, shares issued (per Shares) | shares		6,000,000
Common stock, par or stated value per share (USD per share) | $ / shares		$ 0.01
Payments to acquire equity method investments		$ 200,000,000
Equity method investment, non-cash consideration		$ 5,000,000
Number of shares contingently issuable (Per Share) | shares		200,000
Contingent consideration, stock price trigger (USD per share) | $ / shares		$ 50.00
Equity method investment, contingent consideration, threshold consecutive trading days		30 days
Equity method investments					259,000,000		$ 252,600,000
Equity method investment, difference between carrying amount and underlying equity					$ 11,900,000
Impairment of equity method investment			$ 245,300,000	$ 0		$ 0
Acquisition-date fair value of pre-existing non-controlling interest	$ 449,000,000
Alon USA Energy, Inc. | Loans Payable | Unsecured Promissory Note, Alon
Schedule of Equity Method Investments [Line Items]
Debt instrument, face amount		$ 145,000,000.0						$ 120,000,000.0
Joint Ventures | Delek Logistics Partners, LP
Schedule of Equity Method Investments [Line Items]
Equity method investments				106,500,000
Joint Ventures | Delek Renewables, LLC
Schedule of Equity Method Investments [Line Items]
Equity method investments				2,200,000
Joint Ventures | Delek US Holdings, Inc.
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	50.00%
Equity method investments				$ 29,400,000
Number of joint ventures | joint_venture	2
Alon USA Energy, Inc.
Schedule of Equity Method Investments [Line Items]
Noncash or part noncash acquisition, noncash financial or equity instrument consideration, shares issued (per Shares) | shares	19,250,795.088
Alon USA Energy, Inc. | Alon USA Energy, Inc.
Schedule of Equity Method Investments [Line Items]
Gain on remeasuring equity method investment	$ 196,400,000
Loss on reversal of AOCI	6,300,000
Gain on remeasurement of equity method investment	$ 190,100,000