Retirement Benefits (Plan Assets Target Allocation) (Details) - Defined Benefit Pension Plan	Sep. 30, 2023	Sep. 30, 2022
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)	19.00%	17.00%
U.S. | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	72.00%	73.00%
U.S. | Real estate/other
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	8.00%	10.00%
U.S. | Cash
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	1.00%	0.00%
U.S. | Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	17.00%
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)	3.00%
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)	29.00%
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)	5.00%
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)	19.00%	31.00%
International | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	80.00%	68.00%
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)	1.00%	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)	70.00%
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)	30.00%
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%