COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - CAD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Changes in AOCI
Balance at the beginning of the period	$ 64,483
Other comprehensive income/(loss) retained in AOCI	1,937	$ (947)
Total before tax impact	1,968	(934)
Income tax on amounts retained in AOCI	(30)	(23)
Income tax on amounts reclassified to earnings	(7)	(2)
Tax impact	(37)	(25)
Balance at the end of the period	70,253	64,038
Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	12	23
Commodity contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	(1)	(1)
Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	31
Other contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings		1
Total
Changes in AOCI
Balance at the beginning of the period	2,303	3,520
Balance at the end of the period	4,234	2,561
Cash Flow Hedges
Changes in AOCI
Balance at the beginning of the period	320	121
Other comprehensive income/(loss) retained in AOCI	156	126
Total before tax impact	167	149
Income tax on amounts retained in AOCI	(36)	(23)
Income tax on amounts reclassified to earnings	(2)	(4)
Tax impact	(38)	(27)
Balance at the end of the period	449	243
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	12	23
Cash Flow Hedges | Commodity contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	(1)	(1)
Cash Flow Hedges | Other contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings		1
Excluded Components of Fair Value Hedges
Changes in AOCI
Balance at the beginning of the period	(23)	(35)
Other comprehensive income/(loss) retained in AOCI	(26)	9
Total before tax impact	5	9
Income tax on amounts retained in AOCI	6
Income tax on amounts reclassified to earnings	(7)
Tax impact	(1)	0
Balance at the end of the period	(19)	(26)
Excluded Components of Fair Value Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	31
Net Investment Hedges
Changes in AOCI
Balance at the beginning of the period	(728)	(1,137)
Other comprehensive income/(loss) retained in AOCI	(538)	400
Total before tax impact	(538)	400
Tax impact	0	0
Balance at the end of the period	(1,266)	(737)
Cumulative Translation Adjustment
Changes in AOCI
Balance at the beginning of the period	2,653	4,348
Other comprehensive income/(loss) retained in AOCI	2,344	(1,482)
Total before tax impact	2,344	(1,482)
Tax impact	0	0
Balance at the end of the period	4,997	2,866
Equity Investees
Changes in AOCI
Balance at the beginning of the period	11	5
Other comprehensive income/(loss) retained in AOCI	1
Total before tax impact	1	0
Tax impact	0	0
Balance at the end of the period	12	5
Pension and OPEB Adjustment
Changes in AOCI
Balance at the beginning of the period	70	218
Other comprehensive (income)/loss reclassified to earnings	(11)	(10)
Total before tax impact	(11)	(10)
Income tax on amounts reclassified to earnings	2	2
Tax impact	2	2
Balance at the end of the period	$ 61	$ 210