Share capital - Schedule of Shares Redeemed Under Buyback Program (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | 15 Months Ended | ||||
|---|---|---|---|---|---|---|---|
Sep. 19, 2025 |
Aug. 20, 2025 |
Jun. 23, 2025 |
Mar. 19, 2025 |
Mar. 31, 2026 |
Dec. 31, 2025 |
Mar. 31, 2026 |
|
| Equity [Abstract] | |||||||
| Total number of shares purchased (in shares) | 866,512 | 560,100 | 1,717,181 | 1,360,537 | 0 | 4,504,330 | 4,504,330 |
| Average price paid per share (in USD per share) | $ 173.33 | $ 178.20 | $ 145.59 | $ 183.75 | $ 166.51 | $ 166.51 | |
| Approximate dollar value of shares that may yet be purchased under the program (in millions) | $ 750.0 | $ 900.2 | $ 500.0 | $ 750.0 | $ 750.0 | $ 750.0 |