Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenues	$ 7,284.6	$ 5,390.0	$ 19,664.9	$ 13,910.8
Cost of sales	5,212.6	4,084.7	14,196.0	10,619.7
Selling, general and administrative expense	655.7	527.5	1,863.2	1,450.1
Gain on sale of assets	0.0	0.0	(14.0)	(59.5)
Loss on extinguishment of debt	18.1	0.0	18.1	0.0
Other (income) expense	(17.4)	(4.6)	(28.2)	(26.4)
Income before income taxes	1,415.6	782.4	3,629.8	1,926.9
Income tax expense	299.1	149.5	784.1	377.6
Net income	1,116.5	632.9	2,845.7	1,549.3
Net income (loss) attributable to noncontrolling interests	1.0	2.2	8.9	4.6
Net income attributable to D.R. Horton, Inc.	$ 1,115.5	$ 630.7	$ 2,836.8	$ 1,544.7
Basic net income per common share attributable to D.R. Horton, Inc. (in dollars per share)	$ 3.10	$ 1.73	$ 7.83	$ 4.22
Weighted average number of common shares	359.7	363.8	362.2	366.0
Diluted net income per common share attributable to D.R. Horton, Inc. (in dollars per share)	$ 3.06	$ 1.72	$ 7.73	$ 4.17
Adjusted weighted average number of common shares	364.0	367.7	367.1	370.4