Common Stock Rollforward of Outstanding Shares (Details) - shares shares in Thousands |
12 Months Ended | ||
|---|---|---|---|
Apr. 30, 2021 |
Apr. 30, 2020 |
Apr. 30, 2019 |
|
| Class of Stock [Line Items] | |||
| Beginning balance | 478,209 | 477,172 | 481,001 |
| Acquisition of treasury stock | 0 | (16) | (4,357) |
| Stock issued under compensation plans | 520 | 1,053 | 528 |
| Ending balance | 478,729 | 478,209 | 477,172 |
| Common stock, Class A, voting [Member] | |||
| Class of Stock [Line Items] | |||
| Beginning balance | 169,040 | 168,999 | 169,062 |
| Acquisition of treasury stock | 0 | (13) | (145) |
| Stock issued under compensation plans | 70 | 54 | 82 |
| Ending balance | 169,110 | 169,040 | 168,999 |
| Common Stock, Class B, nonvoting [Member] | |||
| Class of Stock [Line Items] | |||
| Beginning balance | 309,169 | 308,173 | 311,939 |
| Acquisition of treasury stock | 0 | (3) | (4,212) |
| Stock issued under compensation plans | 450 | 999 | 446 |
| Ending balance | 309,619 | 309,169 | 308,173 |