Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 7,267.1	$ 4,197.9	$ 4,782.0
Operating costs and expenses:
Cost of goods sold	6,327.6	3,812.9	4,236.9
Operating expenses	429.0	249.3	270.3
Insurance proceeds — business interruption	0.0	(42.4)	0.0
General and administrative expenses	169.8	106.1	100.6
Depreciation and amortization	153.3	116.4	106.0
Other operating expense (income), net	1.0	4.8	(0.5)
Total operating costs and expenses	7,080.7	4,247.1	4,713.3
Operating income (loss)	186.4	(49.2)	68.7
Interest expense	93.8	54.4	52.1
Interest income	(4.0)	(1.5)	(1.1)
(Income) loss from equity method investments	(12.6)	43.4	(2.0)
Loss on impairment of equity method investment	0.0	245.3	0.0
Gain on remeasurement of equity method investment	(190.1)	0.0	0.0
Other expense (income), net	0.0	0.4	(1.6)
Total non-operating (income) expenses, net	(112.9)	342.0	47.4
Income (loss) from continuing operations before income tax benefit	299.3	(391.2)	21.3
Income tax benefit	(29.2)	(171.5)	(15.8)
Income (loss) from continuing operations	328.5	(219.7)	37.1
(Loss) income from discontinued operations	(8.6)	144.2	5.7
Income tax (benefit) expense	(2.7)	57.9	(0.9)
(Loss) income from discontinued operations, net of tax	(5.9)	86.3	6.6
Net income (loss)	322.6	(133.4)	43.7
Net income attributed to non-controlling interests	33.8	20.3	24.3
Net income (loss) attributable to Delek	$ 288.8	$ (153.7)	$ 19.4
Basic income (loss) per share:
Income (loss) from continuing operations (USD per share)	$ 4.12	$ (3.88)	$ 0.21
(Loss) income from discontinued operations (USD per share)	(0.08)	1.39	0.11
Total basic income (loss) per share (USD per share)	4.04	(2.49)	0.32
Diluted income (loss) per share:
Income (loss) from continuing operations (USD per share)	4.08	(3.88)	0.21
(Loss) income from discontinued operations (USD per share)	(0.08)	1.39	0.11
Total diluted income (loss) per share (USD per share)	$ 4.00	$ (2.49)	$ 0.32
Weighted average common shares outstanding:
Basic (in shares)	71,566,225	61,921,787	60,819,771
Diluted (in shares)	72,303,083	61,921,787	61,320,570
Dividends declared per common share outstanding	$ 0.6	$ 0.6	$ 0.60