Supplemental Guarantor Information - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
ASSETS
Cash and cash equivalents	$ 1,150.3	$ 1,303.2	$ 1,268.7	$ 1,383.8
Investments in subsidiaries	0.0	0.0
Property and equipment, net	218.4	195.4
Other assets	496.1	499.6
Intercompany receivables	0.0	0.0
Total assets	11,712.1	11,558.9
LIABILITIES & EQUITY
Accounts payable and other liabilities	1,512.7	1,494.6
Intercompany payables	0.0	0.0
Notes payable	3,217.6	3,271.3
Total liabilities	4,730.3	4,765.9
Stockholders’ equity	6,981.3	6,792.5
Noncontrolling interests	0.5	0.5
Total equity	6,981.8	6,793.0
Total liabilities and equity	11,712.1	11,558.9
Eliminations [Member]
ASSETS
Cash and cash equivalents	0.0	0.0	0.0	0.0
Investments in subsidiaries	(4,234.3)	(4,118.6)
Property and equipment, net	(5.2)	(5.2)
Other assets	0.0	0.0
Intercompany receivables	(1,517.8)	(1,604.5)
Total assets	(5,757.3)	(5,728.3)
LIABILITIES & EQUITY
Accounts payable and other liabilities	(1.8)	(1.8)
Intercompany payables	(1,517.8)	(1,604.5)
Notes payable	0.0	0.0
Total liabilities	(1,519.6)	(1,606.3)
Stockholders’ equity	(4,237.7)	(4,122.0)
Noncontrolling interests	0.0	0.0
Total equity	(4,237.7)	(4,122.0)
Total liabilities and equity	(5,757.3)	(5,728.3)
D.R. Horton, Inc. [Member]
ASSETS
Cash and cash equivalents	1,012.2	1,076.4	1,166.1	1,217.7
Investments in subsidiaries	4,234.3	4,118.6
Property and equipment, net	81.7	72.0
Other assets	169.7	168.7
Intercompany receivables	1,517.8	1,604.5
Total assets	10,273.1	10,029.0
LIABILITIES & EQUITY
Accounts payable and other liabilities	497.7	444.1
Intercompany payables	0.0	0.0
Notes payable	2,790.7	2,789.0
Total liabilities	3,288.4	3,233.1
Stockholders’ equity	6,984.7	6,795.9
Noncontrolling interests	0.0	0.0
Total equity	6,984.7	6,795.9
Total liabilities and equity	10,273.1	10,029.0
Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	61.2	154.0	34.2	94.6
Investments in subsidiaries	0.0	0.0
Property and equipment, net	55.0	49.9
Other assets	261.2	274.2
Intercompany receivables	0.0	0.0
Total assets	6,291.0	6,300.0
LIABILITIES & EQUITY
Accounts payable and other liabilities	900.4	933.1
Intercompany payables	1,293.5	1,417.1
Notes payable	7.9	9.3
Total liabilities	2,201.8	2,359.5
Stockholders’ equity	4,089.2	3,940.5
Noncontrolling interests	0.0	0.0
Total equity	4,089.2	3,940.5
Total liabilities and equity	6,291.0	6,300.0
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	76.9	72.8	$ 68.4	$ 71.5
Investments in subsidiaries	0.0	0.0
Property and equipment, net	86.9	78.7
Other assets	65.2	56.7
Intercompany receivables	0.0	0.0
Total assets	905.3	958.2
LIABILITIES & EQUITY
Accounts payable and other liabilities	116.4	119.2
Intercompany payables	224.3	187.4
Notes payable	419.0	473.0
Total liabilities	759.7	779.6
Stockholders’ equity	145.1	178.1
Noncontrolling interests	0.5	0.5
Total equity	145.6	178.6
Total liabilities and equity	905.3	958.2
Homebuilding [Member]
ASSETS
Cash and cash equivalents	1,115.5	1,271.8
Restricted cash	8.8	9.5
Inventories	8,742.4	8,340.9
Deferred income taxes	467.8	476.3
Property and equipment, net	154.1	139.5
Other assets	444.7	456.2
Goodwill	80.0	80.0
Total assets	11,013.3	10,774.2
LIABILITIES & EQUITY
Notes payable	2,798.6	2,798.3
Total liabilities	4,272.1	4,252.4
Homebuilding [Member] | Eliminations [Member]
ASSETS
Restricted cash	0.0	0.0
Inventories	0.0	0.0
Deferred income taxes	0.0	0.0
Goodwill	0.0	0.0
Homebuilding [Member] | D.R. Horton, Inc. [Member]
ASSETS
Restricted cash	7.0	7.4
Inventories	3,092.0	2,822.1
Deferred income taxes	158.4	159.3
Goodwill	0.0	0.0
Homebuilding [Member] | Guarantor Subsidiaries [Member]
ASSETS
Restricted cash	1.8	2.1
Inventories	5,525.3	5,425.7
Deferred income taxes	306.5	314.1
Goodwill	80.0	80.0
Homebuilding [Member] | Non-Guarantor Subsidiaries [Member]
ASSETS
Restricted cash	0.0	0.0
Inventories	125.1	93.1
Deferred income taxes	2.9	2.9
Goodwill	0.0	0.0
Financial Services and Other [Member]
ASSETS
Cash and cash equivalents	34.8	31.4
Property and equipment, net	64.3	55.9
Other assets	51.4	43.4
Mortgage loans held for sale	548.3	654.0
Total assets	698.8	784.7
LIABILITIES & EQUITY
Total liabilities	458.2	513.5
Financial Services and Other [Member] | Eliminations [Member]
ASSETS
Mortgage loans held for sale	0.0	0.0
Financial Services and Other [Member] | D.R. Horton, Inc. [Member]
ASSETS
Mortgage loans held for sale	0.0	0.0
Financial Services and Other [Member] | Guarantor Subsidiaries [Member]
ASSETS
Mortgage loans held for sale	0.0	0.0
Financial Services and Other [Member] | Non-Guarantor Subsidiaries [Member]
ASSETS
Mortgage loans held for sale	$ 548.3	$ 654.0