COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - CAD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Changes in AOCI
Balance at beginning of year	$ 68,893
Other comprehensive income/(loss) retained in AOCI	55	$ 1,380
Other comprehensive (income)/loss reclassified to earnings	66	1,394
Income tax on amounts retained in AOCI	10	(30)
Income tax on amounts reclassified to earnings	(3)	(3)
Tax impact	7	(33)
Balance at end of year	71,280	67,303
Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	8
Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	12	19
Total
Changes in AOCI
Balance at beginning of year	7,115	2,303
Balance at end of year	7,188	3,664
Cash Flow Hedges
Changes in AOCI
Balance at beginning of year	407	320
Other comprehensive income/(loss) retained in AOCI	(35)	144
Other comprehensive (income)/loss reclassified to earnings	(27)	144
Income tax on amounts retained in AOCI	9	(34)
Income tax on amounts reclassified to earnings	(2)	0
Tax impact	7	(34)
Balance at end of year	387	430
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	8
Excluded Components of Fair Value Hedges
Changes in AOCI
Balance at beginning of year	(14)	(23)
Other comprehensive income/(loss) retained in AOCI	(6)	(15)
Other comprehensive (income)/loss reclassified to earnings	6	4
Income tax on amounts retained in AOCI	1	4
Income tax on amounts reclassified to earnings	(3)	(4)
Tax impact	(2)	0
Balance at end of year	(10)	(19)
Excluded Components of Fair Value Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	12	19
Net Investment Hedges
Changes in AOCI
Balance at beginning of year	(2,033)	(728)
Other comprehensive income/(loss) retained in AOCI	(34)	(377)
Other comprehensive (income)/loss reclassified to earnings	(34)	(377)
Tax impact	0	0
Balance at end of year	(2,067)	(1,105)
Cumulative Translation Adjustment
Changes in AOCI
Balance at beginning of year	8,452	2,653
Other comprehensive income/(loss) retained in AOCI	118	1,629
Other comprehensive (income)/loss reclassified to earnings	118	1,629
Tax impact	0	0
Balance at end of year	8,570	4,282
Equity Investees and Other Investments
Changes in AOCI
Balance at beginning of year	1	11
Other comprehensive income/(loss) retained in AOCI	12	(1)
Other comprehensive (income)/loss reclassified to earnings	12	(1)
Tax impact	0	0
Balance at end of year	13	10
Pension and OPEB Adjustment
Changes in AOCI
Balance at beginning of year	302	70
Other comprehensive (income)/loss reclassified to earnings	(9)	(5)
Other comprehensive (income)/loss reclassified to earnings	(9)	(5)
Income tax on amounts reclassified to earnings	2	1
Tax impact	2	1
Balance at end of year	$ 295	$ 66