Supplemental Guarantor Information - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017
ASSETS
Cash and cash equivalents	$ 864.2			$ 1,473.1
Restricted cash	21.1			32.9
Investment in subsidiaries	0.0			0.0
Inventories	11,702.3			10,395.0
Mortgage loans held for sale	954.9			796.4
Deferred income taxes, net	173.9			194.0
Property and equipment, net	454.2			401.1
Other assets	889.9			712.9
Goodwill	163.5			109.2
Intercompany receivables	0.0			0.0
Total assets	15,224.0			14,114.6
LIABILITIES & EQUITY
Accounts payable and other liabilities	1,958.7			1,752.2
Intercompany payables	0.0			0.0
Notes payable	3,450.6			3,203.5
Total liabilities	5,409.3			4,955.7
Stockholders’ equity	9,642.4			8,984.4
Noncontrolling interests	172.3			174.5
Total equity	9,814.7	$ 9,534.0	$ 9,298.2	9,158.9	$ 8,769.9	$ 8,371.9	$ 8,055.4	$ 7,747.6
Total liabilities and equity	15,224.0			14,114.6
Eliminations [Member]
ASSETS
Cash and cash equivalents	0.0			0.0
Restricted cash	0.0			0.0
Investment in subsidiaries	(7,055.5)			(6,344.9)
Inventories	(28.4)			(11.2)
Mortgage loans held for sale	0.0			0.0
Deferred income taxes, net	3.6			2.5
Property and equipment, net	(4.4)			(6.9)
Other assets	(83.7)			(45.2)
Goodwill	0.0			0.0
Intercompany receivables	(270.4)			(273.5)
Total assets	(7,438.8)			(6,679.2)
LIABILITIES & EQUITY
Accounts payable and other liabilities	(92.4)			(49.1)
Intercompany payables	(270.4)			(273.5)
Notes payable	0.0			0.0
Total liabilities	(362.8)			(322.6)
Stockholders’ equity	(7,078.5)			(6,355.6)
Noncontrolling interests	2.5			(1.0)
Total equity	(7,076.0)			(6,356.6)
Total liabilities and equity	(7,438.8)			(6,679.2)
D.R. Horton, Inc. [Member]
ASSETS
Cash and cash equivalents	412.7			908.1
Restricted cash	7.7			6.6
Investment in subsidiaries	7,055.5			6,344.9
Inventories	4,315.7			4,037.1
Mortgage loans held for sale	0.0			0.0
Deferred income taxes, net	61.4			69.2
Property and equipment, net	124.8			111.2
Other assets	382.2			306.6
Goodwill	0.0			0.0
Intercompany receivables	58.7			246.2
Total assets	12,418.7			12,029.9
LIABILITIES & EQUITY
Accounts payable and other liabilities	646.2			590.8
Intercompany payables	0.0			0.0
Notes payable	2,107.2			2,443.9
Total liabilities	2,753.4			3,034.7
Stockholders’ equity	9,665.3			8,995.2
Noncontrolling interests	0.0			0.0
Total equity	9,665.3			8,995.2
Total liabilities and equity	12,418.7			12,029.9
Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	115.3			158.7
Restricted cash	2.1			2.0
Investment in subsidiaries	0.0			0.0
Inventories	6,271.7			5,824.1
Mortgage loans held for sale	0.0			0.0
Deferred income taxes, net	90.5			105.0
Property and equipment, net	76.2			66.1
Other assets	440.7			361.3
Goodwill	134.3			80.0
Intercompany receivables	211.7			27.3
Total assets	7,342.5			6,624.5
LIABILITIES & EQUITY
Accounts payable and other liabilities	1,074.1			1,000.4
Intercompany payables	0.0			0.0
Notes payable	6.7			2.1
Total liabilities	1,080.8			1,002.5
Stockholders’ equity	6,261.7			5,622.0
Noncontrolling interests	0.0			0.0
Total equity	6,261.7			5,622.0
Total liabilities and equity	7,342.5			6,624.5
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	336.2			406.3
Restricted cash	11.3			24.3
Investment in subsidiaries	0.0			0.0
Inventories	1,143.3			545.0
Mortgage loans held for sale	954.9			796.4
Deferred income taxes, net	18.4			17.3
Property and equipment, net	257.6			230.7
Other assets	150.7			90.2
Goodwill	29.2			29.2
Intercompany receivables	0.0			0.0
Total assets	2,901.6			2,139.4
LIABILITIES & EQUITY
Accounts payable and other liabilities	330.8			210.1
Intercompany payables	270.4			273.5
Notes payable	1,336.7			757.5
Total liabilities	1,937.9			1,241.1
Stockholders’ equity	793.9			722.8
Noncontrolling interests	169.8			175.5
Total equity	963.7			898.3
Total liabilities and equity	$ 2,901.6			$ 2,139.4