Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenues	$ 20,311.1	$ 17,592.9	$ 16,068.0
Cost of sales	15,373.2	13,720.9	12,398.1
Selling, general and administrative expense	2,047.8	1,832.5	1,676.8
Equity in earnings of unconsolidated entities	(0.7)	(0.5)	(2.8)
Gain on sale of assets	(59.5)	(53.9)	(18.8)
Other (income) expense	(32.7)	(31.4)	(45.3)
Income before income taxes	2,983.0	2,125.3	2,060.0
Income tax expense	602.5	506.7	597.7
Net income	2,380.5	1,618.6	1,462.3
Net income attributable to noncontrolling interests	6.8	0.1	2.0
Net income attributable to D.R. Horton, Inc.	$ 2,373.7	$ 1,618.5	$ 1,460.3
Other comprehensive income, net of income tax:
Basic net income per common share attributable to D.R. Horton, Inc.	$ 6.49	$ 4.34	$ 3.88
Weighted average number of common shares	365.5	372.6	376.6
Diluted net income per common share attributable to D.R. Horton, Inc.	$ 6.41	$ 4.29	$ 3.81
Adjusted weighted average number of common shares	370.2	377.4	383.4