Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Earnings Per Share Reconciliation [Abstract]
Net Income (Loss) Attributable to Parent	$ 4,756.4	$ 4,745.7	$ 5,857.5
Denominator:
Denominator for basic earnings per share - weighted average common shares	329.5	340.7	351.7
Effect of dilutive securities:
Employee stock awards	2.1	2.6	3.1
Denominator for diluted earnings per share - adjusted weighted average common shares	331.6	343.3	354.8
Basic net income per common share attributable to D.R. Horton, Inc.	$ 14.44	$ 13.93	$ 16.65
Diluted net income per common share attributable to D.R. Horton, Inc.	$ 14.34	$ 13.82	$ 16.51