COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - CAD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Changes in AOCI
Balance at beginning of year	$ 68,893
Other comprehensive income/(loss) retained in AOCI	(2,863)	$ 1,937
Other comprehensive (income)/loss reclassified to earnings	(2,863)	1,968
Income tax on amounts retained in AOCI	(14)	(30)
Income tax on amounts reclassified to earnings	6	(7)
Tax impact	(8)	(37)
Balance at end of year	68,358	70,253
Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	17	12
Commodity contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings		(1)
Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	(3)	31
Total
Changes in AOCI
Balance at beginning of year	7,115	2,303
Balance at end of year	4,244	4,234
Cash Flow Hedges
Changes in AOCI
Balance at beginning of year	407	320
Other comprehensive (income)/loss reclassified to earnings	2	167
Income tax on amounts retained in AOCI	2	(36)
Income tax on amounts reclassified to earnings	(3)	(2)
Tax impact	(1)	(38)
Balance at end of year	408	449
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	17	12
Cash Flow Hedges | Commodity contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings		(1)
Cash Flow Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	0
Cash Flow Hedges
Changes in AOCI
Other comprehensive income/(loss) retained in AOCI	(15)	156
Excluded Components of Fair Value Hedges
Changes in AOCI
Balance at beginning of year	(14)	(23)
Other comprehensive income/(loss) retained in AOCI	12	(26)
Other comprehensive (income)/loss reclassified to earnings	9	5
Income tax on amounts retained in AOCI	(3)	6
Income tax on amounts reclassified to earnings	8	(7)
Tax impact	5	(1)
Balance at end of year	(0)	(19)
Excluded Components of Fair Value Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	(3)	31
Net Investment Hedges
Changes in AOCI
Balance at beginning of year	(2,033)	(728)
Other comprehensive income/(loss) retained in AOCI	413	(538)
Other comprehensive (income)/loss reclassified to earnings	413	(538)
Tax impact	0	0
Balance at end of year	(1,620)	(1,266)
Cumulative Translation Adjustment
Changes in AOCI
Balance at beginning of year	8,452	2,653
Other comprehensive (income)/loss reclassified to earnings	(3,356)	2,344
Tax impact	0	0
Balance at end of year	5,096	4,997
Cumulative Translation Adjustment
Changes in AOCI
Other comprehensive income/(loss) retained in AOCI	(3,356)	2,344
Equity Investees and Other Investments
Changes in AOCI
Balance at beginning of year	1	11
Other comprehensive income/(loss) retained in AOCI	21	1
Other comprehensive (income)/loss reclassified to earnings	21	1
Income tax on amounts retained in AOCI	0
Tax impact	0	0
Balance at end of year	22	12
Pension and OPEB Adjustment
Changes in AOCI
Balance at beginning of year	302	70
Other comprehensive income/(loss) retained in AOCI	62
Other comprehensive (income)/loss reclassified to earnings	(14)	(11)
Other comprehensive (income)/loss reclassified to earnings	48	(11)
Income tax on amounts retained in AOCI	(13)
Income tax on amounts reclassified to earnings	1	2
Tax impact	(12)	2
Balance at end of year	$ 338	$ 61