COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - CAD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Changes in AOCI
Balance at the beginning of the period	$ 64,483
Other comprehensive income/(loss) retained in AOCI	1,125	$ 380
Total before tax impact	1,175	428
Income tax on amounts retained in AOCI	4	(118)
Income tax on amounts reclassified to earnings	(10)	(3)
Tax impact	(6)	(121)
Balance at the end of the period	68,778	68,474
Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	22	63
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	43
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	3,472	3,827
Cash Flow Hedges
Changes in AOCI
Balance at the beginning of the period	320	121
Other comprehensive income/(loss) retained in AOCI	15	447
Total before tax impact	36	511
Income tax on amounts retained in AOCI	(4)	(117)
Income tax on amounts reclassified to earnings	(3)	(6)
Tax impact	(7)	(123)
Balance at the end of the period	349	509
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	22	63
Cash Flow Hedges | Commodity contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	(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	(34)	11
Total before tax impact	9	11
Income tax on amounts retained in AOCI	8
Income tax on amounts reclassified to earnings	(10)
Tax impact	(2)	0
Balance at the end of the period	(16)	(24)
Excluded Components of Fair Value Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive (income)/loss reclassified to earnings	43
Net Investment Hedges
Changes in AOCI
Balance at the beginning of the period	(728)	(1,137)
Other comprehensive income/(loss) retained in AOCI	(357)	42
Total before tax impact	(357)	42
Tax impact	0	0
Balance at the end of the period	(1,085)	(1,095)
Cumulative Translation Adjustment
Changes in AOCI
Balance at the beginning of the period	2,653	4,348
Other comprehensive income/(loss) retained in AOCI	1,498	(128)
Total before tax impact	1,498	(128)
Tax impact	0	0
Balance at the end of the period	4,151	4,220
Equity Investees
Changes in AOCI
Balance at the beginning of the period	11	5
Other comprehensive income/(loss) retained in AOCI	3	8
Total before tax impact	3	8
Income tax on amounts retained in AOCI		(1)
Tax impact	0	(1)
Balance at the end of the period	14	12
Pension and OPEB Adjustment
Changes in AOCI
Balance at the beginning of the period	70	218
Other comprehensive (income)/loss reclassified to earnings	(14)	(16)
Total before tax impact	(14)	(16)
Income tax on amounts reclassified to earnings	3	3
Tax impact	3	3
Balance at the end of the period	$ 59	$ 205