COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Changes in AOCI
Balance at beginning of year	$ 64,483	$ 63,398
Other comprehensive income/(loss) retained in AOCI	4,845	(1,144)	$ 4,816
Other			16
Other comprehensive (income)/loss reclassified to earnings	4,907	(1,187)	5,004
Income tax on amounts retained in AOCI	(81)	(33)	(349)
Income tax on amounts reclassified to earnings	(14)	3	(39)
Tax impact	(95)	(30)	(388)
Balance at end of year	68,893	64,483	63,398
Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	31	28	186
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	53	(47)	(4)
Other contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings			4
Total
Changes in AOCI
Balance at beginning of year	2,303	3,520	(1,096)
Balance at end of year	7,115	2,303	3,520
Cash Flow Hedges
Changes in AOCI
Balance at beginning of year	320	121	(897)
Other comprehensive income/(loss) retained in AOCI	79	232	1,125
Other			0
Other comprehensive (income)/loss reclassified to earnings	109	260	1,311
Income tax on amounts retained in AOCI	(15)	(47)	(250)
Income tax on amounts reclassified to earnings	(7)	(14)	(43)
Tax impact	(22)	(61)	(293)
Balance at end of year	407	320	121
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	31	28	186
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	0	(4)
Cash Flow Hedges | Other contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings			4
Excluded Components of Fair Value Hedges
Changes in AOCI
Balance at beginning of year	(23)	(35)	0
Other comprehensive income/(loss) retained in AOCI	(42)	62	(35)
Other comprehensive (income)/loss reclassified to earnings	11	15	(35)
Income tax on amounts retained in AOCI	10	(14)
Income tax on amounts reclassified to earnings	(12)	11
Tax impact	(2)	(3)	0
Balance at end of year	(14)	(23)	(35)
Excluded Components of Fair Value Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	53	(47)
Net Investment Hedges
Changes in AOCI
Balance at beginning of year	(728)	(1,137)	(166)
Other comprehensive income/(loss) retained in AOCI	(1,305)	409	(971)
Other comprehensive (income)/loss reclassified to earnings	(1,305)	409	(971)
Income tax on amounts retained in AOCI	0
Income tax on amounts reclassified to earnings	0
Tax impact	0	0	0
Balance at end of year	(2,033)	(728)	(1,137)
Cumulative Translation Adjustment
Changes in AOCI
Balance at beginning of year	2,653	4,348	56
Other comprehensive income/(loss) retained in AOCI	5,799	(1,695)	4,292
Other			0
Other comprehensive (income)/loss reclassified to earnings	5,799	(1,695)	4,292
Income tax on amounts retained in AOCI	0
Income tax on amounts reclassified to earnings	0
Tax impact	0	0
Balance at end of year	8,452	2,653	4,348
Equity Investees
Changes in AOCI
Balance at beginning of year	11	5	(5)
Other comprehensive income/(loss) retained in AOCI	(9)	6	(6)
Other			16
Other comprehensive (income)/loss reclassified to earnings	(9)	6	10
Income tax on amounts retained in AOCI	(1)
Income tax on amounts reclassified to earnings	0		0
Tax impact	(1)	0	0
Balance at end of year	1	11	5
Pension and OPEB Adjustment
Changes in AOCI
Balance at beginning of year	70	218	(84)
Other comprehensive income/(loss) retained in AOCI	323	(158)	411
Other comprehensive (income)/loss reclassified to earnings	(21)	(24)	(14)
Other comprehensive (income)/loss reclassified to earnings	302	(182)	397
Income tax on amounts retained in AOCI	(75)	28	(99)
Income tax on amounts reclassified to earnings	5	6	4
Tax impact	(70)	34	(95)
Balance at end of year	$ 302	$ 70	$ 218