Loss per share - Schedule of Anti-dilutive Shares (Details) - shares shares in Millions |
12 Months Ended | ||
|---|---|---|---|
Oct. 31, 2022 |
Oct. 31, 2021 |
Oct. 31, 2020 |
|
| Earnings per share [line items] | |||
| Anti-dilutive shares (in shares) | 35.9 | 36.5 | 5.3 |
| Stock options | |||
| Earnings per share [line items] | |||
| Anti-dilutive shares (in shares) | 4.5 | 5.3 | 5.3 |
| Warrants | |||
| Earnings per share [line items] | |||
| Anti-dilutive shares (in shares) | 23.0 | 0.0 | |
| Convertible debt | |||
| Earnings per share [line items] | |||
| Anti-dilutive shares (in shares) | 29.4 | 7.5 | 0.0 |
| Restricted share units | |||
| Earnings per share [line items] | |||
| Anti-dilutive shares (in shares) | 2.0 | 0.7 | 0.0 |