Retirement Benefits - Weighted-average allocation of the majority of the assets related to defined benefit plans (Details)	Jun. 30, 2023	Jun. 30, 2022
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	30.00%	31.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	45.00%	43.00%
Other investments
Defined Benefit Plan Disclosure [Line Items]
Weighted-average allocation of assets related to defined benefit plans	25.00%	26.00%