Capitalized Interest (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Rollforward of capitalized interest
Capitalized interest, beginning of period	$ 301.0	$ 255.1	$ 286.4	$ 237.4
Interest incurred	50.5	50.6	93.1	96.8
Interest charged to cost of sales	(32.8)	(34.0)	(60.8)	(62.5)
Capitalized interest, end of period	318.7	271.7	318.7	271.7
Financial Services [Member]
Rollforward of capitalized interest
Interest incurred	13.4	9.7	28.3	17.8
Forestar Group [Member]
Rollforward of capitalized interest
Interest incurred	8.2	8.2	16.3	16.4
Rental
Rollforward of capitalized interest
Interest incurred	$ 17.6	$ 13.7	$ 25.8	$ 22.7

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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483013/835-20-50-1

+ Details

Name:	us-gaap_InterestCostsIncurred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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://www.xbrl.org/2009/role/commonPracticeRef
-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

+ Details

Name:	us-gaap_RealEstateInventoryCapitalizedInterestCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_RealEstateInventoryCapitalizedInterestCostsCostOfSales1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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.

+ Details

Name:	us-gaap_RealEstateInventoryCapitalizedInterestCostsRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=dhi_FinancialServicesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=dhi_ForestarGroupMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=dhi_RentalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: