Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Oct. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2022	Oct. 31, 2021
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares issued		399,172,937				397,190,100				399,172,937	397,190,100
Common stock, shares outstanding		343,953,023				356,015,843				343,953,023	356,015,843
Preferred stock, shares issued		0				0				0	0
Amount of stock repurchase authorization													$ 1,000.0
Treasury Stock, Common, Shares										14,000,000
Payments for Repurchase of Common Stock										$ 1,100.0
Amount remaining under stock repurchase authorization		$ 438.3								$ 438.3
Dividends, Common Stock [Abstract]
Cash dividends declared per common share		$ 0.225	$ 0.225	$ 0.225	$ 0.225	$ 0.20	$ 0.20	$ 0.20	$ 0.20
Cash dividends paid per common share		$ 0.225	$ 0.225	$ 0.225	$ 0.225	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.90	$ 0.80	$ 0.70
Forestar Group [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Equity Securities Registered, Value														$ 750.0
At-the-market Equity Offering Program, Common Stock Available for Issuance		$ 298.2								$ 298.2				$ 300.0
At-the-market Equity Offering Program, Common Stock Issued										84,547
Stock Issued During Period, Value, New Issues										$ 1.7
Common Stock Available for Issuance, Value Remaining		$ 748.2								748.2
Dividends, Common Stock [Abstract]
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs										$ 0.1
Subsequent Event [Member]
Dividends, Common Stock [Abstract]
Cash dividends declared per common share	$ 0.25