Retirement Benefits - Pensions, additional information (Details) - Pension Plans, Defined Benefit - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Employer discretionary contribution	$ 200,000
Accumulated benefit obligation for all defined benefit plans	5,184,637	$ 4,751,111
Accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets	5,094,129	4,665,272
Fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets	4,140,395	3,807,859
Projected benefit obligation for pension plans with projected benefit obligations in excess of plan assets	5,427,084	4,970,120
Fair value of plan assets for pension plans with projected benefit obligations in excess of plan assets	4,175,871	$ 3,842,539
Expected cash contributions to defined benefit pension plans in 2019	77,000
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
Estimated future benefit payments in the year ending June 30, 2020	235,709
Estimated future benefit payments in the year ending June 30, 2021	249,814
Estimated future benefit payments in the year ending June 30, 2022	306,446
Estimated future benefit payments in the year ending June 30, 2023	266,915
Estimated future benefit payments in the year ending June 30, 2024	274,452
Estimated future benefit payments in the aggregate for the five years ending June 30, 2025 through June 30, 2029	$ 1,482,681