Supplemental Guarantor Information (Details 1) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Financial Services [Abstract]
Income before income taxes	[1]	$ 300.5	$ 230.1	$ 541.8	$ 450.8
Income tax expense		105.4	82.2	189.0	160.4
Net income		195.1	147.9	352.8	290.4
Comprehensive income		192.5	147.9	351.4	290.4
Homebuilding [Member]
Homebuilding:
Revenues		2,701.0	2,338.5	5,062.1	4,591.5
Cost of sales		2,169.3	1,892.0	4,061.4	3,706.5
Total gross profit		531.7	446.5	1,000.7	885.0
Selling, general and administrative expense		258.2	242.4	501.6	480.4
Equity in (income) of subsidiaries		0.0	0.0	0.0	0.0
Other (income)		(9.6)	(4.5)	(13.0)	(10.1)
Financial Services [Abstract]
Income before income taxes		283.1	208.6	512.1	414.7
Financial Services [Member]
Financial Services [Abstract]
Revenues		66.9	59.5	122.2	109.2
General and administrative expense		51.0	40.7	97.1	78.6
Interest and other (income)		(1.5)	(2.7)	(4.6)	(5.5)
Income before income taxes		17.4	21.5	29.7	36.1
D.R. Horton, Inc. [Member]
Financial Services [Abstract]
Income before income taxes		300.5	230.1	544.3	450.8
Income tax expense		105.4	82.2	189.0	160.4
Net income		195.1	147.9	355.3	290.4
Comprehensive income		192.5	147.9	353.9	290.4
D.R. Horton, Inc. [Member] | Homebuilding [Member]
Homebuilding:
Revenues		864.4	727.0	1,660.0	1,423.8
Cost of sales		694.9	593.7	1,333.7	1,147.7
Total gross profit		169.5	133.3	326.3	276.1
Selling, general and administrative expense		118.8	112.4	230.8	222.6
Equity in (income) of subsidiaries		(244.4)	(208.5)	(442.6)	(396.3)
Other (income)		(5.4)	(0.7)	(6.2)	(1.0)
Financial Services [Abstract]
Income before income taxes		300.5	230.1	544.3	450.8
D.R. Horton, Inc. [Member] | Financial Services [Member]
Financial Services [Abstract]
Revenues		0.0	0.0	0.0	0.0
General and administrative expense		0.0	0.0	0.0	0.0
Interest and other (income)		0.0	0.0	0.0	0.0
Income before income taxes		0.0	0.0	0.0	0.0
Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Income before income taxes		218.7	190.4	407.3	369.7
Income tax expense		76.4	67.7	141.5	130.9
Net income		142.3	122.7	265.8	238.8
Comprehensive income		142.3	122.7	265.8	238.8
Guarantor Subsidiaries [Member] | Homebuilding [Member]
Homebuilding:
Revenues		1,836.6	1,611.5	3,407.5	3,167.7
Cost of sales		1,482.3	1,297.8	2,736.1	2,554.9
Total gross profit		354.3	313.7	671.4	612.8
Selling, general and administrative expense		137.7	124.4	266.9	245.6
Equity in (income) of subsidiaries		0.0	0.0	0.0	0.0
Other (income)		(2.1)	(1.1)	(2.8)	(2.5)
Financial Services [Abstract]
Income before income taxes		218.7	190.4	407.3	369.7
Guarantor Subsidiaries [Member] | Financial Services [Member]
Financial Services [Abstract]
Revenues		0.0	0.0	0.0	0.0
General and administrative expense		0.0	0.0	0.0	0.0
Interest and other (income)		0.0	0.0	0.0	0.0
Income before income taxes		0.0	0.0	0.0	0.0
Non-Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Income before income taxes		25.7	18.1	35.3	26.6
Income tax expense		9.4	6.9	13.1	10.3
Net income		16.3	11.2	22.2	16.3
Comprehensive income		16.3	11.2	22.2	16.3
Non-Guarantor Subsidiaries [Member] | Homebuilding [Member]
Homebuilding:
Revenues		0.0	0.0	0.0	0.0
Cost of sales		(7.9)	0.5	(5.5)	3.9
Total gross profit		7.9	(0.5)	5.5	(3.9)
Selling, general and administrative expense		1.7	5.6	3.9	12.2
Equity in (income) of subsidiaries		0.0	0.0	0.0	0.0
Other (income)		(2.1)	(2.7)	(4.0)	(6.6)
Financial Services [Abstract]
Income before income taxes		8.3	(3.4)	5.6	(9.5)
Non-Guarantor Subsidiaries [Member] | Financial Services [Member]
Financial Services [Abstract]
Revenues		66.9	59.5	122.2	109.2
General and administrative expense		51.0	40.7	97.1	78.6
Interest and other (income)		(1.5)	(2.7)	(4.6)	(5.5)
Income before income taxes		17.4	21.5	29.7	36.1
Eliminations [Member]
Financial Services [Abstract]
Income before income taxes		(244.4)	(208.5)	(445.1)	(396.3)
Income tax expense		(85.8)	(74.6)	(154.6)	(141.2)
Net income		(158.6)	(133.9)	(290.5)	(255.1)
Comprehensive income		(158.6)	(133.9)	(290.5)	(255.1)
Eliminations [Member] | Homebuilding [Member]
Homebuilding:
Revenues		0.0	0.0	(5.4)	0.0
Cost of sales		0.0	0.0	(2.9)	0.0
Total gross profit		0.0	0.0	(2.5)	0.0
Selling, general and administrative expense		0.0	0.0	0.0	0.0
Equity in (income) of subsidiaries		244.4	208.5	442.6	396.3
Other (income)		0.0	0.0	0.0	0.0
Financial Services [Abstract]
Income before income taxes		(244.4)	(208.5)	(445.1)	(396.3)
Eliminations [Member] | Financial Services [Member]
Financial Services [Abstract]
Revenues		0.0	0.0	0.0	0.0
General and administrative expense		0.0	0.0	0.0	0.0
Interest and other (income)		0.0	0.0	0.0	0.0
Income before income taxes		$ 0.0	$ 0.0	$ 0.0	$ 0.0

[1] Expenses maintained at the corporate level consist primarily of interest and property taxes, which are capitalized and amortized to cost of sales or expensed directly, and the expenses related to operating the Company’s corporate office. The amortization of capitalized interest and property taxes is allocated to each segment based on the segment’s cost of sales, while those expenses associated with the corporate office are allocated to each segment based on the segment’s inventory balances.