Properties - Capital Leases Included in Properties (Details) - CAD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finance Leased Assets [Line Items]
Cost	$ 196	$ 180
Accumulated depreciation	85	78
Net book value	111	102
Rolling stock
Finance Leased Assets [Line Items]
Cost	182	170
Accumulated depreciation	79	75
Net book value	103	95
Other
Finance Leased Assets [Line Items]
Cost	14	10
Accumulated depreciation	6	3
Net book value	$ 8	$ 7