Supplemental Guarantor Information - Balance Sheet (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018
ASSETS
Cash and cash equivalents	$ 1,494.3	$ 1,583.3
Restricted cash	19.7	12.6
Investment in subsidiaries	0.0	0.0
Inventories	11,282.0	11,899.2
Mortgage loans held for sale	1,072.0	1,025.1
Deferred income taxes, net	163.1	154.1
Property and equipment, net	499.2	563.4
Other assets	912.8	921.7
Goodwill	163.5	163.5
Intercompany receivables	0.0	0.0
Total assets	15,606.6	16,322.9
LIABILITIES & EQUITY
Accounts payable and other liabilities	1,912.1	2,036.7
Intercompany payables	0.0	0.0
Notes payable	3,399.4	3,783.3
Total liabilities	5,311.5	5,820.0
Stockholders’ equity	10,020.9	10,227.4
Noncontrolling interests	274.2	275.5
Total equity	10,295.1	10,502.9	$ 9,298.2	$ 9,158.9
Total liabilities and equity	15,606.6	16,322.9
Eliminations [Member]
ASSETS
Cash and cash equivalents	0.0	0.0
Restricted cash	0.0	0.0
Investment in subsidiaries	(7,349.8)	(7,595.7)
Inventories	(35.3)	(55.3)
Mortgage loans held for sale	0.0	0.0
Deferred income taxes, net	5.1	8.2
Property and equipment, net	(6.0)	(8.4)
Other assets	(89.5)	(96.2)
Goodwill	0.0	0.0
Intercompany receivables	(825.9)	(825.5)
Total assets	(8,301.4)	(8,572.9)
LIABILITIES & EQUITY
Accounts payable and other liabilities	(91.7)	(101.6)
Intercompany payables	(825.9)	(825.5)
Notes payable	0.0	0.0
Total liabilities	(917.6)	(927.1)
Stockholders’ equity	(7,387.1)	(7,650.7)
Noncontrolling interests	3.3	4.9
Total equity	(7,383.8)	(7,645.8)
Total liabilities and equity	(8,301.4)	(8,572.9)
D.R. Horton, Inc. [Member]
ASSETS
Cash and cash equivalents	877.1	1,069.1
Restricted cash	6.8	4.8
Investment in subsidiaries	7,349.8	7,595.7
Inventories	4,166.1	4,527.1
Mortgage loans held for sale	0.0	0.0
Deferred income taxes, net	60.6	58.9
Property and equipment, net	150.7	158.3
Other assets	371.8	412.6
Goodwill	0.0	0.0
Intercompany receivables	0.0	0.0
Total assets	12,982.9	13,826.5
LIABILITIES & EQUITY
Accounts payable and other liabilities	616.1	719.7
Intercompany payables	352.7	372.8
Notes payable	1,955.9	2,452.5
Total liabilities	2,924.7	3,545.0
Stockholders’ equity	10,058.2	10,281.5
Noncontrolling interests	0.0	0.0
Total equity	10,058.2	10,281.5
Total liabilities and equity	12,982.9	13,826.5
Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	115.8	30.3
Restricted cash	1.3	1.8
Investment in subsidiaries	0.0	0.0
Inventories	5,890.7	6,207.5
Mortgage loans held for sale	0.0	0.0
Deferred income taxes, net	89.4	84.7
Property and equipment, net	86.7	99.9
Other assets	449.6	458.7
Goodwill	134.3	134.3
Intercompany receivables	825.9	825.5
Total assets	7,593.7	7,842.7
LIABILITIES & EQUITY
Accounts payable and other liabilities	1,071.3	1,089.1
Intercompany payables	0.0	0.0
Notes payable	14.2	17.4
Total liabilities	1,085.5	1,106.5
Stockholders’ equity	6,508.2	6,736.2
Noncontrolling interests	0.0	0.0
Total equity	6,508.2	6,736.2
Total liabilities and equity	7,593.7	7,842.7
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	501.4	483.9
Restricted cash	11.6	6.0
Investment in subsidiaries	0.0	0.0
Inventories	1,260.5	1,219.9
Mortgage loans held for sale	1,072.0	1,025.1
Deferred income taxes, net	8.0	2.3
Property and equipment, net	267.8	313.6
Other assets	180.9	146.6
Goodwill	29.2	29.2
Intercompany receivables	0.0	0.0
Total assets	3,331.4	3,226.6
LIABILITIES & EQUITY
Accounts payable and other liabilities	316.4	329.5
Intercompany payables	473.2	452.7
Notes payable	1,429.3	1,313.4
Total liabilities	2,218.9	2,095.6
Stockholders’ equity	841.6	860.4
Noncontrolling interests	270.9	270.6
Total equity	1,112.5	1,131.0
Total liabilities and equity	3,331.4	$ 3,226.6
Single Family [Member] | Assets Leased to Others [Member]
Guarantor Obligations [Line Items]
Prior Period Reclassification Adjustment	37.0
Single Family [Member] | Assets Leased to Others [Member] | D.R. Horton, Inc. [Member]
Guarantor Obligations [Line Items]
Prior Period Reclassification Adjustment	26.9
Single Family [Member] | Assets Leased to Others [Member] | Guarantor Subsidiaries [Member]
Guarantor Obligations [Line Items]
Prior Period Reclassification Adjustment	$ 10.1