Capitalized Interest (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Rollforward of capitalized interest | ||||
| Capitalized interest, beginning of period | $ 485.8 | $ 394.5 | $ 438.7 | $ 355.1 |
| Interest incurred | 73.4 | 71.3 | 189.9 | 173.2 |
| Interest charged to cost of sales | (46.1) | (38.4) | (115.5) | (100.9) |
| Capitalized interest, end of period | 513.1 | 427.4 | 513.1 | 427.4 |
| Financial Services [Member] | ||||
| Rollforward of capitalized interest | ||||
| Interest incurred | 7.6 | 10.3 | 16.6 | 25.8 |
| Forestar Group [Member] | ||||
| Rollforward of capitalized interest | ||||
| Interest incurred | 12.4 | 13.4 | 37.4 | 32.3 |
| Rental | ||||
| Rollforward of capitalized interest | ||||
| Interest incurred | $ 10.1 | $ 16.6 | $ 29.5 | $ 45.3 |