Financial Instruments (Interest Rate Management Contracts and Cross Currency Interest Rate Swaps) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2025	Sep. 30, 2025
Interest Rate Swaps Contracts | Designated as hedging instrument | Fair Value Hedges
Derivative [Line Items]
US$ Notional	$ 600.0	$ 800.0
Average Pay %	Secured Overnight Financing Rate (SOFR) [Member]	Secured Overnight Financing Rate (SOFR) [Member]
Average Receive %	1.80%	1.64%
Years Average Maturity	2 years 4 months 24 days	2 years
Interest Rate Swaps Contracts | Designated as hedging instrument | Cash flow hedges
Derivative [Line Items]
US$ Notional	$ 3,363.0	$ 3,106.0
Average Pay %	2.80%	2.78%
Average Receive %	SOFR	SOFR
Years Average Maturity	19 years 10 months 24 days	20 years 1 month 6 days
Interest Rate Swaps Contracts | Not designated as hedging instrument
Derivative [Line Items]
US$ Notional	$ 135.2	$ 269.1
Average Pay %	3.28%	3.28%
Average Receive %	SOFR	SOFR
Years Average Maturity	19 years 10 months 24 days	20 years 2 months 12 days
Cross currency interest rate swaps(A) | Designated as hedging instrument | Net investment hedges
Derivative [Line Items]
US$ Notional	$ 2,043.8	$ 70.3
Average Pay %	2.09%	4.86%
Average Receive %	3.72%	4.53%
Years Average Maturity	2 years 3 months 18 days	6 months
Cross currency interest rate swaps(A) | Designated as hedging instrument | Cash flow hedges
Derivative [Line Items]
US$ Notional	$ 102.4	$ 247.7
Average Pay %	5.23%	5.21%
Average Receive %	2.94%	3.12%
Years Average Maturity	1 year	1 year 7 months 6 days
Cross currency interest rate swaps(A) | Not designated as hedging instrument
Derivative [Line Items]
US$ Notional	$ 26.5	$ 0.0
Average Pay %	0.15%	0.00%
Average Receive %	1.85%	0.00%
Years Average Maturity	1 year 4 months 24 days	0 years