Debt (NEOM Green Hydrogen Project Financing) (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025
Debt Instrument [Line Items]
Long-term debt proceeds	$ 644.0	$ 3,978.2
Variable Interest Entity, Primary Beneficiary | 2026 Facilities | Nonrecourse
Debt Instrument [Line Items]
Long-term debt proceeds	$ 543.0