Number of Units That Can Be Granted as Percentage of Shares Acquired

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award Grant Date Fair Value

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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Ownership Target, Period

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Share-based Compensation Arrangement by Share-based Payment Award, Ratio Employer Match Per Dollar Contributed

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Share-based Compensation Arrangement by Share-based Payment Award, Trading Days Used to Calculate Average Share Price

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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This item represents the amount of cash contributions during the period made by the entity to the Employee Stock Ownership Plan (ESOP).

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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.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Amount of cash paid to settle liability for award under share-based payment arrangement.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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.

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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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- Definition

Number of non-option equity instruments exercised by participants.

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Number of shares purchased for issuance under share-based payment arrangement.

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Percentage of vesting of award under share-based payment arrangement.

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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.

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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- Definition

Value, before forfeiture, of shares granted under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

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Stock-Based Compensation - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020 CAD ($) shares	Dec. 31, 2020 CAD ($) shares	Dec. 31, 2019 CAD ($) shares	Dec. 31, 2018 CAD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 170.0	$ 133.0	$ 75.0
Share-based liabilities paid		86.0	58.0	37.0
Regular and Performance Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 16.0	14.0	10.0
Expiration period		7 years
Fair value of options at grant date		$ 15.0	14.0	16.0
Unrecognized compensation expense		$ 12.0
Weighted-average period of recognition for unrecognized compensation		1 year 1 month 6 days
Fair value of shares vested for stock option plan		$ 10.0	8.0	11.0
Regular and Performance Stock Options \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		12 months
Regular and Performance Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		48 months
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 89.0	$ 54.0
Units issued \| shares		97,998	133,681	125,280
Grant date fair value		$ 34.0
Payout percentage		200.00%	193.00%
PSUs vested in period \| shares		113,769
Fair value of PSUs vested in period		$ 98.0
Number of trading days			30 days
Share-based liabilities paid	$ 76.0	$ 76.0	$ 54.0	$ 30.0
PSUs units paid in period \| shares	121,225		117,228
Performance Share Units \| Retention Grant
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units issued \| shares			579	36,975
Performance Deferred Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units issued \| shares		10,029
Grant date fair value		$ 4.0
Matching % of DSU's granted to senior managers		25.00%
PSUs and PDSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 121.0
Vesting period		3 years
Unrecognized compensation expense		$ 51.0
Weighted-average period of recognition for unrecognized compensation		1 year 4 months 24 days
Units issued \| shares		108,027
Deferred Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 21.0	$ 20.0	$ 4.0
Vesting period		36 months
Unrecognized compensation expense		$ 1.0
Weighted-average period of recognition for unrecognized compensation		1 year 3 months 18 days
Units issued \| shares		19,041	19,912
Grant date fair value		$ 7.0
Number of trading days		10 days
Share-based liabilities paid		$ 9.0	$ 4.0	6.0
PSUs units paid in period \| shares		26,788	12,110
Matching % of DSU's granted to senior managers		25.00%
Ownership target period		5 years
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 7.0	$ 6.0	$ 5.0
Vesting period		1 year
Employer matching ratio per dollar contributed		0.3333
Maximum percentage of annual salary that an employee can contribute		6.00%
Number of shares purchased on behalf of participants \| shares		115,344	137,942	118,865
Employer contributions		$ 9.0	$ 8.0	$ 6.0