Segment Information - Reconciliation of Comprehensive Income to Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net income (loss) and comprehensive income (loss) attributable to Churchill Downs Incorporated			$ 249.1	$ (81.9)	$ 137.5
Net loss attributable to noncontrolling interest			0.0	0.2	0.3
Net income (loss)			249.1	(82.1)	137.2
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent			0.0	95.4	2.4
Income from continuing operations, net of tax			249.1	13.3	139.6
Depreciation and amortization			103.2	92.9	96.4
Interest expense			84.7	80.0	70.9
Income tax provision (benefit)			94.5	(5.3)	56.8
EBITDA			531.5	180.9	363.7
Stock-based compensation expense			27.8	23.7	23.8
Legal reserves			0.0	0.0	3.6
Other charges			0.2	0.8	0.4
Pre-opening expense			5.8	11.2	5.1
Interest, depreciation and amortization expense related to equity investments			41.5	38.5	32.6
Changes in fair value of Rivers Des Plaines' interest rate swaps			(12.9)	12.9	12.4
Rivers Des Plaines' legal reserves and transactions costs			9.9	0.0	4.7
Other charges and recoveries, net			0.0	0.0	(0.2)
Transaction expense, net			7.9	1.0	5.3
Asset impairments			15.3	17.5	0.0
Total adjustments to EBITDA			95.5	105.6	87.7
Adjusted EBITDA			627.0	286.5	451.4
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA			664.9	325.1	482.8
All Other
Segment Reporting Information [Line Items]
Adjusted EBITDA			(37.9)	(38.6)	(31.4)
Live and Historical Racing
Segment Reporting Information [Line Items]
Asset impairments		$ 11.2
Adjusted EBITDA			175.0	39.1	135.6
Live and Historical Racing | Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA			175.0	39.1	135.6
TwinSpires
Segment Reporting Information [Line Items]
Asset impairments	$ 4.1
Adjusted EBITDA			78.0	112.9	69.3
TwinSpires | Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA			78.0	112.9	69.3
Gaming Segment
Segment Reporting Information [Line Items]
Adjusted EBITDA			411.9	173.1	277.9
Gaming Segment | Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA			$ 411.9	$ 173.1	$ 277.9