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Stock-Based Compensation Plans - Directors' DSU Plan (Details) - Director - DSUs shares in Thousands	12 Months Ended
	Dec. 31, 2023 shares	Dec. 31, 2022 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit with underlying value equivalent to common shares	1
Number of units (thousands)
DSUs outstanding, beginning of year (shares)	224	183
Granted (shares)	40	33
Notional dividends reinvested (shares)	10	8
Paid out (shares)	(33)	0
DSUs outstanding, end of year (shares)	241	224

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