Capitalized Interest (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Rollforward of capitalized interest
Capitalized interest, beginning of period	$ 286.4	$ 237.4
Interest incurred	42.6	46.2
Interest charged to cost of sales	(28.0)	(28.5)
Capitalized interest, end of period	301.0	255.1
Financial Services [Member]
Rollforward of capitalized interest
Interest incurred	14.9	8.1
Forestar Group [Member]
Rollforward of capitalized interest
Interest incurred	8.1	8.2
Rental
Rollforward of capitalized interest
Interest incurred	$ 8.2	$ 9.0

Total interest costs incurred during the period and either capitalized or charged against earnings.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483013/835-20-50-1

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- Definition

Carrying amount as of the balance sheet date of interest costs that were capitalized to properties under development during the land development and construction period of a project, and which are included in inventory.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483013/835-20-50-1

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- Definition

Amount of interest cost charged to cost of sales that had been previously capitalized to inventory.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 20
-Topic 835
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483013/835-20-50-1

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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