Stock-Based Compensation Plans - Stock Options (Narrative) (Details) - CAD ($) $ / shares in Units, shares in Millions, $ in Millions |
12 Months Ended | |
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Dec. 31, 2023 |
Dec. 31, 2022 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Stock options outstanding (shares) | 1.9 | 2.3 |
| Stock options weighted average exercise price (CAD per share) | $ 48.12 | $ 47.72 |
| Options vested, number of options (shares) | 1.6 | 1.5 |
| Options vested, weighted average exercise price (CAD per share) | $ 47.19 | $ 44.86 |
| Options exercised (shares) | 0.3 | 1.0 |
| Proceeds from stock options exercised | $ 13 | $ 26 |
| Stock options, intrinsic value | $ 6 | $ 9 |
| Options | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Exercisable period | 10 years | |
| Expiration period after death or retirement | 3 years | |
| Award vesting period | 4 years | |
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- Definition Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period After Death or Retirement No definition available.
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- Definition Amount of cash inflow from exercise of option under share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Number of options outstanding, including both vested and non-vested options. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Number of share options (or share units) exercised during the current period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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