CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Statement of Comprehensive Income [Abstract] | ||||
| Unrealized gain (loss) from change in pension obligations, tax | $ (0.1) | $ (0.1) | $ (0.2) | $ (0.2) |
| Unrealized loss, other postretirement benefits, tax | 0.0 | 0.0 | 0.0 | 0.0 |
| Unrealized income (loss) on cash flow hedges, tax | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 |