Consolidated statement of comprehensive income - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net income (loss)	$ (526)	$ 1,212	$ (714)	$ 1,505
Other comprehensive income (loss), net of income taxes
Postretirement benefits liability adjustment (excluding amortization)	0	0	(114)	18
Amortization of postretirement benefits liability adjustment included in net periodic benefit costs	34	28	68	55
Total other comprehensive income (loss)	34	28	(46)	73
Comprehensive income (loss)	$ (492)	$ 1,240	$ (760)	$ 1,578