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Shareholders' Equity - Share repurchase program (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 2 Months Ended | 12 Months Ended
--- | --- | ---
Feb. 24, 2026 | Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Class of Stock [Line Items] |  |  |  |
Common shares held in treasury (shares) |  | 240.8 | 219.2 | 218.5
Common shares held in treasury, at cost |  | $ 6,410.0 | $ 4,487.0 |
Authorized Share Repurchase Program |  |  |  |
Class of Stock [Line Items] |  |  |  |
Aggregate cost of shares repurchased |  | $ 1,889.8 | $ 23.5 | $ 0.0
Number of shares repurchased (shares) |  | 21.2 | 0.3 | 0.0
Average price per share repurchased |  | $ 89.26 | $ 89.63 | $ 0
Common shares | Authorized Share Repurchase Program |  |  |  |
Class of Stock [Line Items] |  |  |  |
Remaining share repurchase authorization |  | $ 1,100.0 |  |
Cumulative number of shares acquired since inception of share repurchase program |  | 455.0 |  |
Aggregate purchase price of shares acquired since inception of share repurchase program |  | $ 7,800.0 |  |
Common shares | Authorized Share Repurchase Program | Subsequent Event |  |  |  |
Class of Stock [Line Items] |  |  |  |
Remaining share repurchase authorization | $ 702.0 |  |  |
Aggregate cost of shares repurchased | $ 405.0 |  |  |
Number of shares repurchased (shares) | 4.3 |  |  |

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