Retirement Benefits - Summary of defined benefit pension plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Change in plan assets
Fair value of plan assets at beginning of year	$ 4,244,969
Fair value of plan assets at end of year	4,594,106	$ 4,244,969
Amounts recognized on the Consolidated Balance Sheet
Pensions and other postretirement benefits	(1,887,414)	(1,304,379)
Pension Plans, Defined Benefit
Change in benefit obligation
Benefit obligation at beginning of year	5,487,574	5,033,997
Service cost	82,743	76,647	$ 82,993
Interest cost	142,479	160,542	144,339
Acquisition	380,237	0
Plan amendments	3,286	7,719
Actuarial loss	569,306	491,792
Benefits paid	(232,048)	(237,080)
Foreign currency translation and other	(27,954)	(46,043)
Benefit obligation at end of year	6,405,623	5,487,574	5,033,997
Change in plan assets
Fair value of plan assets at beginning of year	4,244,969	3,915,889
Actual gain on plan assets	253,684	318,809
Acquisition	280,103	0
Employer contributions	72,753	284,965
Benefits paid	(232,048)	(237,080)
Foreign currency translation and other	(25,355)	(37,614)
Fair value of plan assets at end of year	4,594,106	4,244,969	$ 3,915,889
Funded status	(1,811,517)	(1,242,605)
Amounts recognized on the Consolidated Balance Sheet
Other accrued liabilities	(1,423)	(8,396)
Pensions and other postretirement benefits	(1,810,094)	(1,234,209)
Net amount recognized	(1,811,517)	(1,242,605)
Amounts recognized in Accumulated Other Comprehensive (Loss)
Net actuarial loss	1,921,389	1,510,901
Prior service cost	17,184	19,602
Transition obligation	26	44
Net amount recognized	$ 1,938,599	$ 1,530,547