CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2023 CAD ($)	Dec. 31, 2022 CAD ($)		Dec. 31, 2021 CAD ($)
Operating activities
Net income (loss)		$ 3,923	$ 3,517		$ 2,852
Reconciliation of net income to cash provided by operating activities:
Depreciation and amortization (Note 11, 13, 15)		1,543	853		811
Deferred income tax (recovery) expense (Note 6)		(7,885)	136		242
Pension recovery and funding (Note 23)		(306)	(288)		(249)
Equity (earnings) loss of Kansas City Southern (Note 11, 12)		(230)	(1,074)		141
Foreign exchange gain on debt and lease liabilities		0	0		(7)
Remeasurement loss of Kansas City Southern (Note 11)		7,175	0		0
Dividends from Kansas City Southern (Note 12)		300	1,157		0
Settlement of Mexican tax audits (Note 6)		(135)	0		0
Other operating activities, net		60	(67)		(36)
Change in non-cash working capital balances related to operations (Note 22)		(308)	(92)		(66)
Cash provided by operating activities		4,137	4,142		3,688
Investing activities
Additions to properties		(2,468)	(1,557)		(1,532)
Additions to Meridian Speedway properties		(31)	0		0
Investment in Kansas City Southern (Note 11)		0	0		(12,299)
Proceeds from sale of properties and other assets		57	58		96
Cash acquired on control of Kansas City Southern (Note 11)		298	0		0
Investment in government securities (Note 17)		(267)	0		0
Proceeds from settlement of government securities (Note 17)		274	0		0
Other		(25)	3		5
Cash used in investing activities		(2,162)	(1,496)		(13,730)
Financing activities
Dividends paid		(707)	(707)		(507)
Issuance of Common Shares (Note 21)		69	32		25
Issuance of long-term debt, excluding commercial paper (Note 17)		0	0		10,673
Repayment of long-term debt, excluding commercial paper (Note 17)		(2,395)	(571)		(359)
Proceeds from term loan (Note 17)		0	0		633
Repayment of term loan (Note 17)		0	(636)		0
Net issuance (repayment) of commercial paper (Note 17)		1,095	(415)		(454)
Acquisition-related financing fees (Note 11)		(17)	0		(51)
Other		0	0		(24)
Cash (used in) provided by financing activities		(1,955)	(2,297)		9,936
Effect of foreign currency fluctuations on foreign-denominated cash and cash equivalents		(7)	20		41
Cash position
Increase (decrease) in cash and cash equivalents		13	369		(65)
Cash and cash equivalents at beginning of period(1)	[1]	451	82		147
Cash and cash equivalents at end of year		464	451	[1]	82	[1]
Supplemental disclosures of cash flow information:
Income taxes paid		906	408		552
Interest paid		$ 825	$ 641		$ 426

[1] As at January 1, 2022, cash and cash equivalents of $82 million includes $13 million of restricted cash.