Retirement Benefits (Plan Assets Target Allocation) (Details) - Defined Benefit Pension Plan	Sep. 30, 2024	Sep. 30, 2023
U.S.
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	100.00%	100.00%
U.S. | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	20.00%	19.00%
U.S. | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	73.00%	72.00%
U.S. | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	6.00%	8.00%
U.S. | Cash
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	1.00%	1.00%
U.S. | Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	16.00%
U.S. | Minimum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	66.00%
U.S. | Minimum | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	4.00%
U.S. | Minimum | Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
U.S. | Maximum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	27.00%
U.S. | Maximum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	80.00%
U.S. | Maximum | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	7.00%
U.S. | Maximum | Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	100.00%	100.00%
International | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	14.00%	19.00%
International | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	86.00%	80.00%
International | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	0.00%	0.00%
International | Cash
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	0.00%	1.00%
International | Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	5.00%
International | Minimum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	78.00%
International | Minimum | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International | Minimum | Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International | Maximum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	22.00%
International | Maximum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	95.00%
International | Maximum | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
International | Maximum | Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%