Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share Reconciliation [Abstract]
Net Income (Loss) Attributable to Parent	$ 5,857.5	$ 4,175.8	$ 2,373.7
Denominator:
Denominator for basic earnings per share - weighted average common shares	351.7	361.1	365.5
Effect of dilutive securities:
Employee stock awards	3.1	4.7	4.7
Denominator for diluted earnings per share - adjusted weighted average common shares	354.8	365.8	370.2
Basic net income per common share attributable to D.R. Horton, Inc.	$ 16.65	$ 11.56	$ 6.49
Diluted net income per common share attributable to D.R. Horton, Inc.	$ 16.51	$ 11.41	$ 6.41