Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosures [Line Items]
Cash paid for taxes (net of cash refunds)		$ 940.7	$ 615.9	$ 645.2
Cash paid for taxes		395.0
Income tax paid, tax credit		$ 50.0
U.S. federal statutory tax rate		21.00%	21.00%	21.00%
Deemed repatriation tax obligation after application of foreign tax credits		$ 60.8
Business and asset actions, including equity affiliate income		3,700.0
Restructuring Charges Tax Amount		695.2	$ 13.2	$ 34.7
Valuation allowance against deferred tax assets				36.0
Gain on sale of business		67.3	1,575.6	0.0
Business and asset actions		3,747.0	57.0	244.6
Income (loss) from subsidiaries, tax benefit				$ 15.9
Liquified Natural Gas | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Tax Disclosures [Line Items]
Gain on sale of business	$ 1,600.0		$ 1,600.0
Project Exit Costs
Income Tax Disclosures [Line Items]
Business and asset actions, including equity affiliate income		3,700.0
Restructuring Charges Tax Amount		695.2
Other tax expense (benefit)		197.4
Tax provision for uncertain tax positions		11.3
Valuation allowance against deferred tax assets		364.9
Deferred tax assets, future disposition of foreign subsidiaries		$ 167.5