Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Sep. 30, 2013
Homebuilding revenues:
Consolidated revenues	$ 2,147.0		$ 1,692.8		$ 5,552.5		$ 4,399.4
Income (Loss) before Income Taxes
Income (loss) before income taxes	171.8	[1]	205.1	[1]	563.4	[1]	455.1	[1]
Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	2,102.9		1,644.5		5,435.1		4,268.1
Asset Impairment Charges [Abstract]
Inventory Write-down	54.7		0		57.0		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	158.6	[1]	185.4	[1]	532.2	[1]	403.0	[1]
Homebuilding inventories
Total homebuilding inventory	7,375.6	[2]			7,375.6	[2]			6,197.4	[2]
Financial Services [Member]
Homebuilding revenues:
Financial Services Revenue	44.1		48.3		117.4		131.3
Income (Loss) before Income Taxes
Income (loss) before income taxes	13.2	[1]	19.7	[1]	31.2	[1]	52.1	[1]
East [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	251.3		163.3		644.6		454.4
Asset Impairment Charges [Abstract]
Inventory Write-down	2.0		0		2.0		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	13.3	[1]	11.4	[1]	39.0	[1]	26.9	[1]
Homebuilding inventories
Total homebuilding inventory	845.2	[2]			845.2	[2]			742.9	[2]
Midwest [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	133.1		147.6		338.8		329.9
Asset Impairment Charges [Abstract]
Inventory Write-down	48.8		0		48.8		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	(37.2)	[1]	15.6	[1]	(18.1)	[1]	23.5	[1]
Homebuilding inventories
Total homebuilding inventory	440.0	[2]			440.0	[2]			412.2	[2]
Southeast [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	584.4		425.6		1,503.0		1,050.3
Asset Impairment Charges [Abstract]
Inventory Write-down	0.7		0		2.8		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	52.3	[1]	48.5	[1]	156.0	[1]	96.1	[1]
Homebuilding inventories
Total homebuilding inventory	1,860.3	[2]			1,860.3	[2]			1,508.5	[2]
South Central [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	533.3		414.5		1,384.9		1,089.1
Asset Impairment Charges [Abstract]
Inventory Write-down	0		0		0		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	54.0	[1]	44.7	[1]	143.0	[1]	102.4	[1]
Homebuilding inventories
Total homebuilding inventory	1,643.9	[2]			1,643.9	[2]			1,443.6	[2]
Southwest [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	74.1		86.1		207.8		241.0
Asset Impairment Charges [Abstract]
Inventory Write-down	0		0		0		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	8.2	[1]	7.7	[1]	19.7	[1]	24.6	[1]
Homebuilding inventories
Total homebuilding inventory	282.9	[2]			282.9	[2]			262.4	[2]
West [Member] | Homebuilding [Member]
Homebuilding revenues:
Total homebuilding revenues	526.7		407.4		1,356.0		1,103.4
Asset Impairment Charges [Abstract]
Inventory Write-down	3.2		0		3.4		0
Income (Loss) before Income Taxes
Income (loss) before income taxes	68.0	[1]	57.5	[1]	192.6	[1]	129.5	[1]
Homebuilding inventories
Total homebuilding inventory	2,079.4	[2]			2,079.4	[2]			1,668.2	[2]
Corporate and Unallocated [Member] | Homebuilding [Member]
Homebuilding inventories
Total homebuilding inventory	$ 223.9	[2],[3]			$ 223.9	[2],[3]			$ 159.6	[2],[3]

[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 revenue, while those expenses associated with the corporate office are allocated to each segment based on the segment’s inventory balances.

[2] Homebuilding inventories are the only assets included in the measure of homebuilding segment assets used by the Company’s chief operating decision makers.

[3] Corporate and unallocated consists primarily of capitalized interest and property taxes.