Leases Components of Lease Expense (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 77	$ 74
Short-term lease cost	17	16
Variable lease cost	9	5
Sublease Income	(2)	(3)
Finance Lease Cost
Amortization of right-of-use assets	6	10
Interest on lease liabilities	4	10
Total lease costs	$ 111	$ 112