Retirement Benefits (Benefit Liability Exceeds Value of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Pension Plans with PBO in Excess of Plan Assets:
Defined Benefit Plan, Funding Status [Extensible Enumeration]	Defined Benefit Plan, Unfunded Plan [Member]
Pension Plans with ABO in Excess of Plan Assets:
Defined Benefit Plan, Funding Status [Extensible Enumeration]	Defined Benefit Plan, Unfunded Plan [Member]
Defined Benefit Pension Plan
Pension Plans with PBO in Excess of Plan Assets:
PBO	$ 66.5
Pension Plans with ABO in Excess of Plan Assets:
ABO	59.7
Defined Benefit Pension Plan | U.S.
Pension Plans with PBO in Excess of Plan Assets:
PBO	2,356.3	$ 2,446.5
Fair value of plan assets	2,204.7	2,321.1
PBO in excess of plan assets	151.6	125.4
Pension Plans with ABO in Excess of Plan Assets:
ABO	2,313.9	2,394.5
Fair value of plan assets	2,204.7	2,321.1
ABO in excess of plan assets	109.2	73.4
Defined Benefit Pension Plan | International
Pension Plans with PBO in Excess of Plan Assets:
PBO	315.3	326.1
Fair value of plan assets	188.3	207.2
PBO in excess of plan assets	127.0	118.9
Pension Plans with ABO in Excess of Plan Assets:
ABO	152.0	139.8
Fair value of plan assets	45.9	42.0
ABO in excess of plan assets	$ 106.1	$ 97.8