v3.19.2
leases (Details) - CAD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Income from subleasing right-of-use lease assets        
Portion of real estate right-of-use assets that are subleased, as a percent     20.00%  
Co-location sublet revenue included in operating service revenues $ 4 $ 4 $ 9 $ 9
Lease payments $ 81 $ 68 $ 184 $ 136