Common Stock Rollforward of Outstanding Shares (Details) - shares shares in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Class of Stock [Line Items]
Beginning balance	478,729	478,209	477,172
Acquisition of treasury stock	0	0	(16)
Stock issued under compensation plans	291	520	1,053
Ending balance	479,020	478,729	478,209
Common stock, Class A, voting [Member]
Class of Stock [Line Items]
Beginning balance	169,110	169,040	168,999
Acquisition of treasury stock	0	0	(13)
Stock issued under compensation plans	65	70	54
Ending balance	169,175	169,110	169,040
Common Stock, Class B, nonvoting [Member]
Class of Stock [Line Items]
Beginning balance	309,619	309,169	308,173
Acquisition of treasury stock	0	0	(3)
Stock issued under compensation plans	226	450	999
Ending balance	309,845	309,619	309,169