Supplemental Guarantor Information - Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Consolidating Statement of Operations
Revenues	$ 3,519.0	$ 3,332.7
Cost of sales	2,751.1	2,580.1
Selling, general and administrative expense	402.8	384.2
Gain on sale of assets	(2.0)	(13.4)
Other (income) expense	(8.6)	(9.4)
Income before income taxes	375.7	391.2
Income tax expense	89.0	202.4
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	286.7	188.8
Net loss attributable to noncontrolling interests	(0.5)	(0.5)
Net Income (Loss) Attributable to Parent	287.2	189.3
Eliminations [Member]
Consolidating Statement of Operations
Revenues	(29.0)	0.0
Cost of sales	(25.5)	0.0
Selling, general and administrative expense	0.0	0.0
Gain on sale of assets	0.0	0.0
Other (income) expense	0.0	0.0
Income before income taxes	(3.5)	0.0
Income tax expense	(0.8)	0.0
Equity in net income of subsidiaries, net of tax	(195.9)	(143.3)
Net income	(198.6)	(143.3)
Net loss attributable to noncontrolling interests	0.2	0.0
Net Income (Loss) Attributable to Parent	(198.8)	(143.3)
D.R. Horton, Inc. [Member]
Consolidating Statement of Operations
Revenues	1,335.7	1,163.8
Cost of sales	1,057.2	915.4
Selling, general and administrative expense	157.9	152.2
Gain on sale of assets	(2.0)	0.0
Other (income) expense	(0.8)	(0.4)
Income before income taxes	123.4	96.6
Income tax expense	29.2	51.1
Equity in net income of subsidiaries, net of tax	195.9	143.3
Net income	290.1	188.8
Net loss attributable to noncontrolling interests	0.0	0.0
Net Income (Loss) Attributable to Parent	290.1	188.8
Guarantor Subsidiaries [Member]
Consolidating Statement of Operations
Revenues	2,081.7	2,052.4
Cost of sales	1,681.4	1,640.0
Selling, general and administrative expense	165.9	151.5
Gain on sale of assets	0.0	0.0
Other (income) expense	(0.4)	0.0
Income before income taxes	234.8	260.9
Income tax expense	55.8	137.9
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	179.0	123.0
Net loss attributable to noncontrolling interests	0.0	0.0
Net Income (Loss) Attributable to Parent	179.0	123.0
Non-Guarantor Subsidiaries [Member]
Consolidating Statement of Operations
Revenues	130.6	116.5
Cost of sales	38.0	24.7
Selling, general and administrative expense	79.0	80.5
Gain on sale of assets	0.0	(13.4)
Other (income) expense	(7.4)	(9.0)
Income before income taxes	21.0	33.7
Income tax expense	4.8	13.4
Equity in net income of subsidiaries, net of tax	0.0	0.0
Net income	16.2	20.3
Net loss attributable to noncontrolling interests	(0.7)	(0.5)
Net Income (Loss) Attributable to Parent	$ 16.9	$ 20.8