Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other non-operating income (expense), net	Other non-operating income (expense), net
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5.2	$ 6.0
Interest cost	48.5	46.9
Expected return on plan assets	(41.6)	(43.6)
Prior service cost amortization	0.5	0.3
Actuarial loss amortization	17.5	17.8
Curtailments	0.0	(1.9)
Other	0.1	0.3
Net Periodic Cost	30.2	25.8
U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.4	2.7
Interest cost	33.7	32.5
Expected return on plan assets	(30.0)	(31.8)
Prior service cost amortization	0.3	0.3
Actuarial loss amortization	14.3	14.8
Curtailments	0.0	0.0
Other	0.0	0.0
Net Periodic Cost	20.7	18.5
International | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.8	3.3
Interest cost	14.8	14.4
Expected return on plan assets	(11.6)	(11.8)
Prior service cost amortization	0.2	0.0
Actuarial loss amortization	3.2	3.0
Curtailments	0.0	(1.9)
Other	0.1	0.3
Net Periodic Cost	$ 9.5	$ 7.3