Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 27,774.2	$ 20,311.1	$ 17,592.9
Cost of sales	19,899.2	15,373.2	13,720.9
Selling, general and administrative expense	2,556.2	2,047.8	1,832.5
Gain on sale of assets	(14.0)	(59.5)	(53.9)
Loss on extinguishment of debt	18.1	0.0	0.0
Other (income) expense	(41.6)	(33.4)	(31.9)
Income before income taxes	5,356.3	2,983.0	2,125.3
Income tax expense	1,165.1	602.5	506.7
Net income	4,191.2	2,380.5	1,618.6
Net income attributable to noncontrolling interests	15.4	6.8	0.1
Net income attributable to D.R. Horton, Inc.	$ 4,175.8	$ 2,373.7	$ 1,618.5
Other comprehensive income, net of income tax:
Basic net income per common share attributable to D.R. Horton, Inc.	$ 11.56	$ 6.49	$ 4.34
Weighted average number of common shares	361.1	365.5	372.6
Diluted net income per common share attributable to D.R. Horton, Inc.	$ 11.41	$ 6.41	$ 4.29
Adjusted weighted average number of common shares	365.8	370.2	377.4