Retirement Benefits (Plan Assets Target Allocation) (Details) - Defined Benefit Pension Plan	Sep. 30, 2025	Sep. 30, 2024
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)	16.00%	20.00%
U.S. \| Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	72.00%	73.00%
U.S. \| Real estate
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	5.00%	6.00%
U.S. \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	6.00%	0.00%
U.S. \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
Actual allocation (percent)	1.00%	1.00%
U.S. \| Minimum \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	15.00%
U.S. \| Minimum \| Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	60.00%
U.S. \| Minimum \| Real estate
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	5.00%
U.S. \| Minimum \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	5.00%
U.S. \| Maximum \| Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	25.00%
U.S. \| Maximum \| Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	74.00%
U.S. \| Maximum \| Real estate
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	8.00%
U.S. \| Maximum \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	8.00%
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%	14.00%
International \| Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	77.00%	78.00%
International \| Real estate
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
Actual allocation (percent)	0.00%	0.00%
International \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Actual allocation (percent)	9.00%	8.00%
International \| Cash
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	0.00%
Actual allocation (percent)	0.00%	0.00%
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 \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	4.00%
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)	87.00%
International \| Maximum \| Alternative credit
Defined Benefit Plan Disclosure [Line Items]
Target allocation (percent)	12.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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