Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
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 Nonoperating Income (Expense), Net	Other Nonoperating Income (Expense), Net	Other Nonoperating Income (Expense), Net
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 39.8	$ 44.7	$ 46.7
Interest cost	102.8	94.1	116.0
Expected return on plan assets	(235.7)	(277.9)	(266.1)
Prior service cost amortization	1.3	1.2	1.2
Actuarial loss amortization	80.7	97.8	103.2
Settlements	6.2	1.8	5.2
Other	1.3	1.0	0.8
Net Periodic (Benefit) Cost	(3.6)	(37.3)	7.0
Defined Benefit Pension Plan | U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	18.3	21.3	23.4
Interest cost	73.9	68.9	91.2
Expected return on plan assets	(168.3)	(194.5)	(188.7)
Prior service cost amortization	1.3	1.2	1.2
Actuarial loss amortization	66.0	78.5	83.7
Settlements	6.0	1.3	5.0
Other	0.0	0.0	0.0
Net Periodic (Benefit) Cost	(2.8)	(23.3)	15.8
Defined Benefit Pension Plan | International
Defined Benefit Plan Disclosure [Line Items]
Service cost	21.5	23.4	23.3
Interest cost	28.9	25.2	24.8
Expected return on plan assets	(67.4)	(83.4)	(77.4)
Prior service cost amortization	0.0	0.0	0.0
Actuarial loss amortization	14.7	19.3	19.5
Settlements	0.2	0.5	0.2
Other	1.3	1.0	0.8
Net Periodic (Benefit) Cost	$ (0.8)	$ (14.0)	$ (8.8)