Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Retained Earnings	Treasury Stock	Non-Controlling Interest in Subsidiaries	Commodity contracts	Commodity contracts Accumulated Other Comprehensive Income	Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings
Beginning balance (shares) at Dec. 31, 2018		90,478,075				(12,477,780)
Beginning balance at Dec. 31, 2018	$ 1,808.1	$ 0.9	$ 1,135.4	$ 28.6	$ 981.8	$ (514.1)	$ 175.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	298.2				277.9		20.3
Other comprehensive income (loss) related to commodity contracts, net								$ (18.4)	$ (18.4)
Common stock dividends	(64.3)				(64.3)		0.0
Distribution to non-controlling interest	(23.8)						(23.8)
Equity-based compensation expense	$ 19.2		18.9				0.3
Repurchase of common stock (shares)	(4,175,576)					(4,175,576)
Repurchase of common stock	$ (147.8)					$ (147.8)	0.0
Taxes due to the net settlement of equity-based compensation	(8.4)		(8.4)				0.0
Exercise of equity-based awards (shares)		462,318
Other	0.6		0.2	0.5	(0.1)	0.0	0.0
Ending balance at Sep. 30, 2019	$ 1,863.4	$ 0.9	1,146.1	10.7	1,195.3	$ (661.9)	172.3
Ending balance (shares) at Sep. 30, 2019		90,940,393				(16,653,356)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends per share (USD per share)	$ 0.84
Beginning balance (shares) at Jun. 30, 2019		90,861,698				(15,416,502)
Beginning balance at Jun. 30, 2019	$ 1,886.2	$ 0.9	1,140.3	26.3	1,165.9	$ (618.9)	171.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	60.0				51.3		8.7
Other comprehensive income (loss) related to commodity contracts, net								(15.7)	(15.7)
Common stock dividends	(21.8)				(21.8)		0.0
Distribution to non-controlling interest	(8.2)						(8.2)
Equity-based compensation expense	$ 7.4		7.3				0.1
Repurchase of common stock (shares)	(1,236,854)					(1,236,854)
Repurchase of common stock	$ (43.0)					$ (43.0)	0.0
Taxes due to the net settlement of equity-based compensation	(1.5)		(1.5)
Exercise of equity-based awards (shares)		78,695
Other	0.0		0.0	0.1	(0.1)	0.0	0.0
Ending balance at Sep. 30, 2019	$ 1,863.4	$ 0.9	1,146.1	10.7	1,195.3	$ (661.9)	172.3
Ending balance (shares) at Sep. 30, 2019		90,940,393				(16,653,356)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends per share (USD per share)	$ 0.29
Beginning balance (shares) at Dec. 31, 2019		90,987,025				(17,516,814)
Beginning balance at Dec. 31, 2019	$ 1,835.3	$ 0.9	1,151.9	0.1	1,205.6	$ (692.2)	169.0			$ (6.5)	$ (6.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(285.4)				(314.8)		29.4
Other comprehensive income (loss) related to commodity contracts, net								(0.2)	(0.2)
Common stock dividends	(69.0)				(69.0)		0.0
Distribution to non-controlling interest	(25.0)						(25.0)
Equity-based compensation expense	$ 17.7		17.6				0.1
Repurchase of common stock (shares)	(58,713)					(58,713)
Repurchase of common stock	$ (1.9)					$ (1.9)	0.0
Repurchase of Non-Controlling Interest	(28.9)		(24.3)				(4.6)
Impact from IDR Simplification transaction of Delek Logistics LP	(13.6)		37.2				(50.8)
Taxes due to the net settlement of equity-based compensation	$ (2.3)		(2.3)				0.0
Exercise of equity-based awards (shares)	314,204	314,204
Other	$ 0.1		0.0	0.1	0.0	0.0	0.0
Ending balance at Sep. 30, 2020	$ 1,420.3	$ 0.9	1,180.1	0.0	815.3	$ (694.1)	118.1
Ending balance (shares) at Sep. 30, 2020		91,301,229				(17,575,527)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends per share (USD per share)	$ 0.93
Beginning balance (shares) at Jun. 30, 2020		91,232,964				(17,575,527)
Beginning balance at Jun. 30, 2020	$ 1,559.3	$ 0.9	1,160.1	0.5	926.4	$ (694.1)	165.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(76.9)				(88.1)		11.2
Other comprehensive income (loss) related to commodity contracts, net								$ (0.5)	$ (0.5)
Common stock dividends	(23.0)				(23.0)
Distribution to non-controlling interest	(8.2)						(8.2)
Equity-based compensation expense	6.7		6.7
Repurchase of Non-Controlling Interest	(23.1)		(23.5)				0.4
Impact from IDR Simplification transaction of Delek Logistics LP	(13.6)		37.2				(50.8)
Taxes due to the net settlement of equity-based compensation	$ (0.4)		(0.4)
Exercise of equity-based awards (shares)	68,265	68,265
Ending balance at Sep. 30, 2020	$ 1,420.3	$ 0.9	$ 1,180.1	$ 0.0	$ 815.3	$ (694.1)	$ 118.1
Ending balance (shares) at Sep. 30, 2020		91,301,229				(17,575,527)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock dividends per share (USD per share)	$ 0.31