Supplemental Guarantor Information - Consolidating Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Unaudited Supplemental Consolidating Statement of Operations
Goodwill impairment									$ 7.2	$ 9.8	$ 0.0
Income before income taxes	$ 433.0	$ 378.6	$ 300.5	$ 241.3	$ 338.8	$ 333.8	$ 230.1	$ 220.7	1,353.5	1,123.4	814.2
Income tax expense (benefit)	149.4	128.8	105.4	83.6	99.9	112.4	82.2	78.2	467.2	372.7	280.7
Net income	283.6	249.8	195.1	157.7	238.9	221.4	147.9	142.5	886.3	750.7	533.5
Comprehensive income									884.9	749.9	533.8
Homebuilding [Member]
Unaudited Supplemental Consolidating Statement of Operations
Revenues									11,861.8	10,559.0	7,858.5
Cost of sales									9,502.6	8,535.7	6,268.6
Gross profit	732.6	$ 625.8	$ 531.7	$ 468.9	582.3	$ 556.0	$ 446.5	$ 438.6	2,359.2	2,023.3	1,589.9
Selling, general and administrative expense									1,100.3	1,003.0	826.9
Goodwill impairment	$ 7.2				$ 9.8				7.2	9.8	0.0
Equity in (income) of subsidiaries									0.0	0.0	0.0
Other (income)									(12.7)	(7.8)	(5.5)
Income before income taxes									1,264.4	1,018.3	768.5
Financial Services [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									89.1	105.1	45.7
Financial Services [Abstract]
Revenues, net of recourse and reinsurance expense									295.6	265.0	166.4
General and administrative expense									220.0	183.0	138.5
Interest and other income									(13.5)	(23.1)	(17.8)
D.R Horton, Inc. [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									1,358.7	1,123.4	814.2
Income tax expense (benefit)									469.0	372.7	280.7
Net income									889.7	750.7	533.5
Comprehensive income									888.3	750.7	533.5
D.R Horton, Inc. [Member] | Homebuilding [Member]
Unaudited Supplemental Consolidating Statement of Operations
Revenues									3,947.5	3,334.6	2,547.4
Cost of sales									3,163.6	2,698.1	2,038.0
Gross profit									783.9	636.5	509.4
Selling, general and administrative expense									503.8	461.2	388.3
Goodwill impairment									0.0	0.0
Equity in (income) of subsidiaries									(1,071.0)	(945.9)	(691.8)
Other (income)									(7.6)	(2.2)	(1.3)
Income before income taxes									1,358.7	1,123.4	814.2
D.R Horton, Inc. [Member] | Financial Services [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									0.0	0.0	0.0
Financial Services [Abstract]
Revenues, net of recourse and reinsurance expense									0.0	0.0	0.0
General and administrative expense									0.0	0.0	0.0
Interest and other income									0.0	0.0	0.0
Guarantor Subsidiaries [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									976.8	846.4	647.7
Income tax expense (benefit)									334.9	277.2	222.1
Net income									641.9	569.2	425.6
Comprehensive income									641.9	568.4	425.9
Guarantor Subsidiaries [Member] | Homebuilding [Member]
Unaudited Supplemental Consolidating Statement of Operations
Revenues									7,930.3	7,224.4	5,299.9
Cost of sales									6,357.5	5,834.3	4,222.5
Gross profit									1,572.8	1,390.1	1,077.4
Selling, general and administrative expense									592.7	538.8	433.0
Goodwill impairment									7.2	9.8
Equity in (income) of subsidiaries									0.0	0.0	0.0
Other (income)									(3.9)	(4.9)	(3.3)
Income before income taxes									976.8	846.4	647.7
Guarantor Subsidiaries [Member] | Financial Services [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									0.0	0.0	0.0
Financial Services [Abstract]
Revenues, net of recourse and reinsurance expense									0.0	0.0	0.0
General and administrative expense									0.0	0.0	0.0
Interest and other income									0.0	0.0	0.0
Non-Guarantor Subsidiaries [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									94.2	99.5	44.1
Income tax expense (benefit)									35.5	37.4	16.6
Net income									58.7	62.1	27.5
Comprehensive income									58.7	62.1	27.5
Non-Guarantor Subsidiaries [Member] | Homebuilding [Member]
Unaudited Supplemental Consolidating Statement of Operations
Revenues									0.0	0.0	11.2
Cost of sales									(7.7)	3.3	8.1
Gross profit									7.7	(3.3)	3.1
Selling, general and administrative expense									3.8	3.0	5.6
Goodwill impairment									0.0	0.0
Equity in (income) of subsidiaries									0.0	0.0	0.0
Other (income)									(1.2)	(0.7)	(0.9)
Income before income taxes									5.1	(5.6)	(1.6)
Non-Guarantor Subsidiaries [Member] | Financial Services [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									89.1	105.1	45.7
Financial Services [Abstract]
Revenues, net of recourse and reinsurance expense									295.6	265.0	166.4
General and administrative expense									220.0	183.0	138.5
Interest and other income									(13.5)	(23.1)	(17.8)
Consolidation, Eliminations [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									(1,076.2)	(945.9)	(691.8)
Income tax expense (benefit)									(372.2)	(314.6)	(238.7)
Net income									(704.0)	(631.3)	(453.1)
Comprehensive income									(704.0)	(631.3)	(453.1)
Consolidation, Eliminations [Member] | Homebuilding [Member]
Unaudited Supplemental Consolidating Statement of Operations
Revenues									(16.0)	0.0	0.0
Cost of sales									(10.8)	0.0	0.0
Gross profit									(5.2)	0.0	0.0
Selling, general and administrative expense									0.0	0.0	0.0
Goodwill impairment									0.0	0.0
Equity in (income) of subsidiaries									1,071.0	945.9	691.8
Other (income)									0.0	0.0	0.0
Income before income taxes									(1,076.2)	(945.9)	(691.8)
Consolidation, Eliminations [Member] | Financial Services [Member]
Unaudited Supplemental Consolidating Statement of Operations
Income before income taxes									0.0	0.0	0.0
Financial Services [Abstract]
Revenues, net of recourse and reinsurance expense									0.0	0.0	0.0
General and administrative expense									0.0	0.0	0.0
Interest and other income									$ 0.0	$ 0.0	$ 0.0