Note 9. Stock Compensation Plans Deferred Share Units (Details) - Non-Employee Directors Stock Compensation Deferral Plan - Deferred Share Units Director Compensation - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Share-based Compensation Arrangements
Share-based Compensation Arrangements, Grants in Period	39,032	34,480	37,132
Share-based Compensation Arrangements, Grants in Period, Weighted Average Grant Date Fair Value	$ 23.07	$ 24.87	$ 15.35
Share-based Compensation Arrangements, Vested in Period, Fair Value	$ 0.9	$ 0.9	$ 0.6
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	0