CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 3,923	$ 3,517	$ 2,852
Net (loss) gain in foreign currency translation adjustments, net of hedging activities	(655)	1,628	(291)
Change in derivatives designated as cash flow hedges	7	6	48
Change in pension and post-retirement defined benefit plans	(73)	680	1,286
Other comprehensive income (loss) from equity investees	7	(5)	9
Other comprehensive (loss) income before income taxes	(714)	2,309	1,052
Income tax expense on above items	(4)	(115)	(341)
Net other comprehensive income (loss)	(718)	2,194	711
Comprehensive income	3,205	5,711	3,563
Comprehensive loss attributable to the non-controlling interest	(13)	0	0
Comprehensive income attributable to controlling shareholders	$ 3,218	$ 5,711	$ 3,563