Retirement Benefits - Schedule of Health Care Cost trend Rate Assumptions Used to Measure the Postretirement Benefit Obligations (Details) - Other Postretirement Benefits	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year (as percent)	9.73%	10.35%
Ultimate health care cost trend rate	4.50%	4.50%
Year that the ultimate rate is reached	2035	2034