Retirement Benefit Obligations - Schedule of Weighted-Average Asset Allocations, by Asset Category (Detail)	Jun. 30, 2022	Jun. 30, 2021
Asset Category:
Benefit plan weighted-average asset allocations	100.00%	100.00%
Equity securities
Asset Category:
Benefit plan weighted-average asset allocations	15.00%	19.00%
Debt securities
Asset Category:
Benefit plan weighted-average asset allocations	75.00%	73.00%
Cash and other
Asset Category:
Benefit plan weighted-average asset allocations	10.00%	8.00%