Retirement Benefits - Weighted-average allocation of the majority of the assets related to defined benefit plans (Details)	Jun. 30, 2024	Jun. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	100.00%	100.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	26.00%	30.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	49.00%	45.00%
Other investments
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	25.00%	25.00%