Supplemental Guarantor Information - Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financial Services [Abstract]
Income before income taxes	$ 318.1	$ 241.3
Income tax expense	111.2	83.6
Net income	206.9	157.7
Comprehensive income	206.9	158.9
Eliminations [Member]
Financial Services [Abstract]
Income before income taxes	(255.3)	(198.2)
Income tax expense	(89.4)	(68.8)
Net income	(165.9)	(129.4)
Comprehensive income	(165.9)	(129.4)
D.R. Horton, Inc. [Member]
Financial Services [Abstract]
Income before income taxes	318.1	241.3
Income tax expense	111.2	83.6
Net income	206.9	157.7
Comprehensive income	206.9	158.9
Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Income before income taxes	228.1	188.6
Income tax expense	79.2	65.1
Net income	148.9	123.5
Comprehensive income	148.9	123.5
Non-Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Income before income taxes	27.2	9.6
Income tax expense	10.2	3.7
Net income	17.0	5.9
Comprehensive income	17.0	5.9
Homebuilding [Member]
Homebuilding:
Revenues	2,826.1	2,361.1
Cost of sales	2,267.9	1,892.2
Total gross profit	558.2	468.9
Selling, general and administrative expense	268.4	241.7
Equity in (income) of subsidiaries	0.0	0.0
Other (income) expense	(4.1)	(1.7)
Financial Services [Abstract]
Income before income taxes	293.9	228.9
Homebuilding [Member] | Eliminations [Member]
Homebuilding:
Revenues	0.0	(5.4)
Cost of sales	0.0	(2.9)
Total gross profit	0.0	(2.5)
Selling, general and administrative expense	0.0	0.0
Equity in (income) of subsidiaries	255.3	195.7
Other (income) expense	0.0	0.0
Financial Services [Abstract]
Income before income taxes	(255.3)	(198.2)
Homebuilding [Member] | D.R. Horton, Inc. [Member]
Homebuilding:
Revenues	918.1	795.6
Cost of sales	735.4	638.9
Total gross profit	182.7	156.7
Selling, general and administrative expense	124.0	111.9
Equity in (income) of subsidiaries	(255.3)	(195.7)
Other (income) expense	(4.1)	(0.8)
Financial Services [Abstract]
Income before income taxes	318.1	241.3
Homebuilding [Member] | Guarantor Subsidiaries [Member]
Homebuilding:
Revenues	1,896.1	1,570.9
Cost of sales	1,524.7	1,253.8
Total gross profit	371.4	317.1
Selling, general and administrative expense	143.3	129.2
Equity in (income) of subsidiaries	0.0	0.0
Other (income) expense	0.0	(0.7)
Financial Services [Abstract]
Income before income taxes	228.1	188.6
Homebuilding [Member] | Non-Guarantor Subsidiaries [Member]
Homebuilding:
Revenues	11.9	0.0
Cost of sales	7.8	2.4
Total gross profit	4.1	(2.4)
Selling, general and administrative expense	1.1	0.6
Equity in (income) of subsidiaries	0.0	0.0
Other (income) expense	0.0	(0.2)
Financial Services [Abstract]
Income before income taxes	3.0	(2.8)
Financial Services and Other [Member]
Financial Services [Abstract]
Revenues	78.1	55.3
General and administrative expense	57.5	47.7
Interest and other (income) expense	(3.6)	(4.8)
Income before income taxes	24.2	12.4
Financial Services and Other [Member] | Eliminations [Member]
Financial Services [Abstract]
Revenues	0.0	0.0
General and administrative expense	0.0	0.0
Interest and other (income) expense	0.0	0.0
Income before income taxes	0.0	0.0
Financial Services and Other [Member] | D.R. Horton, Inc. [Member]
Financial Services [Abstract]
Revenues	0.0	0.0
General and administrative expense	0.0	0.0
Interest and other (income) expense	0.0	0.0
Income before income taxes	0.0	0.0
Financial Services and Other [Member] | Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Revenues	0.0	0.0
General and administrative expense	0.0	0.0
Interest and other (income) expense	0.0	0.0
Income before income taxes	0.0	0.0
Financial Services and Other [Member] | Non-Guarantor Subsidiaries [Member]
Financial Services [Abstract]
Revenues	78.1	55.3
General and administrative expense	57.5	47.7
Interest and other (income) expense	(3.6)	(4.8)
Income before income taxes	$ 24.2	$ 12.4