Fair Value Measurements (Schedule of Nonrecurring Fair Value Measurements) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2026	Sep. 30, 2025
Long Lived Assets Held-for-sale [Line Items]
Plant and equipment, net	$ 24,995.1	$ 25,337.8
Fair Value, Nonrecurring | Project Exit Costs
Long Lived Assets Held-for-sale [Line Items]
Assets held for sale	461.6
Plant and equipment, net	201.2
Fair Value, Nonrecurring | Project Exit Costs | Level 1
Long Lived Assets Held-for-sale [Line Items]
Assets held for sale	0.0
Plant and equipment, net	0.0
Fair Value, Nonrecurring | Project Exit Costs | Level 2
Long Lived Assets Held-for-sale [Line Items]
Assets held for sale	0.0
Plant and equipment, net	0.0
Fair Value, Nonrecurring | Project Exit Costs | Level 3
Long Lived Assets Held-for-sale [Line Items]
Assets held for sale	461.6
Plant and equipment, net	201.2
Fair Value, Nonrecurring | Project Exit Costs | Location, Statement of Financial Position, Activity, Capitalization [Axis]: us-gaap:AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent
Long Lived Assets Held-for-sale [Line Items]
Impairment of property and equipment		$ 350.6
Fair Value, Nonrecurring | Project Exit Costs | Location, Statement of Financial Position, Activity, Capitalization [Axis]: us-gaap:PropertyPlantAndEquipmentNet
Long Lived Assets Held-for-sale [Line Items]
Impairment of property and equipment	$ 2,200.0