Supplemental Guarantor Information - Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Consolidating Statement of Operations
Revenues	$ 4,020.7	$ 3,519.0
Cost of sales	3,084.2	2,751.1
Selling, general and administrative expense	455.8	402.8
Gain on sale of assets	(31.1)	(2.0)
Other (income) expense	(11.5)	(8.6)
Income before income taxes	523.3	375.7
Income tax expense	90.8	89.0
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	432.5	286.7
Net income (loss) attributable to noncontrolling interests	1.2	(0.5)
Net Income (Loss) Attributable to Parent	431.3	287.2
Eliminations [Member]
Consolidating Statement of Operations
Revenues	(227.6)	(29.0)
Cost of sales	(206.9)	(25.5)
Selling, general and administrative expense	0.0	0.0
Gain on sale of assets	(1.8)	0.0
Other (income) expense	0.0	0.0
Income before income taxes	(18.9)	(3.5)
Income tax expense	(3.1)	(0.8)
Equity in net income of subsidiaries, net of tax	(291.4)	(195.9)
Net income	(307.2)	(198.6)
Net income (loss) attributable to noncontrolling interests	1.1	0.2
Net Income (Loss) Attributable to Parent	(308.3)	(198.8)
D.R. Horton, Inc. [Member]
Consolidating Statement of Operations
Revenues	1,593.6	1,335.7
Cost of sales	1,232.4	1,057.2
Selling, general and administrative expense	177.3	157.9
Gain on sale of assets	0.0	(2.0)
Other (income) expense	(4.1)	(0.8)
Income before income taxes	188.0	123.4
Income tax expense	31.2	29.2
Equity in net income of subsidiaries, net of tax	291.4	195.9
Net income	448.2	290.1
Net income (loss) attributable to noncontrolling interests	0.0	0.0
Net Income (Loss) Attributable to Parent	448.2	290.1
Guarantor Subsidiaries [Member]
Consolidating Statement of Operations
Revenues	2,294.4	2,081.7
Cost of sales	1,841.0	1,681.4
Selling, general and administrative expense	180.3	165.9
Gain on sale of assets	0.0	0.0
Other (income) expense	(0.3)	(0.4)
Income before income taxes	273.4	234.8
Income tax expense	45.4	55.8
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	228.0	179.0
Net income (loss) attributable to noncontrolling interests	0.0	0.0
Net Income (Loss) Attributable to Parent	228.0	179.0
Non-Guarantor Subsidiaries [Member]
Consolidating Statement of Operations
Revenues	360.3	130.6
Cost of sales	217.7	38.0
Selling, general and administrative expense	98.2	79.0
Gain on sale of assets	(29.3)	0.0
Other (income) expense	(7.1)	(7.4)
Income before income taxes	80.8	21.0
Income tax expense	17.3	4.8
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	63.5	16.2
Net income (loss) attributable to noncontrolling interests	0.1	(0.7)
Net Income (Loss) Attributable to Parent	$ 63.4	$ 16.9