Retirement Benefits - Net periodic pension cost recognized (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 84,188	$ 82,743	$ 76,647
Interest cost	102,475	142,479	160,542
Expected return on plan assets	(267,579)	(266,674)	(251,072)
Amortization of prior service cost	5,325	5,633	6,655
Amortization of unrecognized actuarial loss	207,897	165,815	121,823
Amortization of transition obligation	18	18	18
Net periodic benefit cost	$ 132,324	$ 130,014	$ 114,613