Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenues	$ 5,933.4	$ 4,020.7
Cost of sales	4,332.5	3,084.2
Selling, general and administrative expense	585.9	455.8
Gain on sale of assets	(14.0)	(31.1)
Other (income) expense	(5.3)	(11.5)
Income before income taxes	1,034.3	523.3
Income tax expense	239.1	90.8
Net income	795.2	432.5
Net income (loss) attributable to noncontrolling interests	3.4	1.2
Net income attributable to D.R. Horton, Inc.	$ 791.8	$ 431.3
Basic net income per common share attributable to D.R. Horton, Inc. (in dollars per share)	$ 2.17	$ 1.17
Weighted average number of common shares	364.4	368.3
Diluted net income per common share attributable to D.R. Horton, Inc. (in dollars per share)	$ 2.14	$ 1.16
Adjusted weighted average number of common shares	370.0	373.4