Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Oct. 31, 2023	Oct. 31, 2021
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common stock, shares issued		401,202,253				399,172,937				401,202,253	399,172,937
Common stock, shares outstanding		334,848,565				343,953,023				334,848,565	343,953,023
Preferred stock, shares issued		0				0				0	0
Amount of stock repurchase authorization		$ 1,000.0								$ 1,000.0
Treasury Stock, Common, Shares										11,100,000
Payments for Repurchase of Common Stock										$ 1,200.0
Amount remaining under stock repurchase authorization		$ 234.0								$ 234.0
Dividends, Common Stock [Abstract]
Cash dividends declared per common share		$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.225	$ 0.225	$ 0.225	$ 0.225
Cash dividends paid per common share		$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.225	$ 0.225	$ 0.225	$ 0.225	$ 1.00	$ 0.90	$ 0.80
Forestar Group [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Equity Securities Registered, Value		$ 750.0								$ 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										0
Common Stock Available for Issuance, Value Remaining		$ 748.2								$ 748.2
Subsequent Event [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Amount of stock repurchase authorization													$ 1,500.0
Amount remaining under stock repurchase authorization													$ 32.8
Dividends, Common Stock [Abstract]
Cash dividends declared per common share	$ 0.30