v3.26.1
Notes Payable - Homebuilding Textuals (Details) - USD ($)
$ in Millions
9 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Sep. 30, 2025
Debt Instrument [Line Items]      
Letters of Credit Outstanding, Amount $ 285.4    
Notes payable 7,112.6   $ 5,965.5
HomeBuildingOps      
Debt Instrument [Line Items]      
Line of Credit Facility, Current Borrowing Capacity 3,300.0 $ 2,300.0  
Line of Credit Facility, Maximum Borrowing Capacity $ 4,000.0    
Letters of credit, sublimit borrowing capacity, as a percentage 100.00%    
Borrowings outstanding on revolving credit facility $ 500.0   0.0
Letters of Credit Outstanding, Amount 240.3    
Line of Credit Facility, Remaining Borrowing Capacity 2,600.0    
Authorized Repurchase Of Debt Securities 500.0    
Debt Repurchase Authorization Remaining 500.0    
Notes payable $ 3,685.3   $ 3,154.4
Line of Credit Facility, Interest Rate at Period End 4.50%    
HomeBuildingOps | Senior Notes      
Debt Instrument [Line Items]      
Notes payable $ 3,000.0    
HomeBuildingOps | Credit Facility Maturing December 18, 2029      
Debt Instrument [Line Items]      
Line of Credit Facility, Current Borrowing Capacity $ 2,000.0    
Line of Credit Facility, Expiration Date Mar. 27, 2031    
HomeBuildingOps | Credit Facility Maturing October 28, 2027      
Debt Instrument [Line Items]      
Line of Credit Facility, Current Borrowing Capacity $ 265.0    
Line of Credit Facility, Expiration Date Oct. 28, 2027    
HomeBuildingOps | Credit Facility Maturing March 27, 2029      
Debt Instrument [Line Items]      
Line of Credit Facility, Current Borrowing Capacity $ 1,000.0    
Line of Credit Facility, Expiration Date Mar. 27, 2029