COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - CAD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Changes in AOCI
Balance at the beginning of the period	$ 63,398
Other comprehensive income/(loss) retained in AOCI	(125)	$ (175)
Total before tax impact	(121)	(104)
Income tax on amounts retained in AOCI	28	(92)
Income tax on amounts reclassified to earnings	(1)	(16)
Tax impact	27	(108)
Balance at the end of the period	65,025	64,273
Interest rate contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	8	76
Foreign exchange contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings		(4)
Other contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	1	2
Total
Changes in AOCI
Balance at the beginning of the period	3,520	(1,096)
Balance at the end of the period	3,426	(1,308)
Cash Flow Hedges
Changes in AOCI
Balance at the beginning of the period	121	(897)
Other comprehensive income/(loss) retained in AOCI	(90)	384
Total before tax impact	(81)	458
Income tax on amounts retained in AOCI	28	(92)
Income tax on amounts reclassified to earnings	(2)	(17)
Tax impact	26	(109)
Balance at the end of the period	66	(548)
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	8	76
Cash Flow Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings		(4)
Cash Flow Hedges | Other contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	1	2
Excluded Components of Fair Value Hedges
Changes in AOCI
Balance at the beginning of the period	(35)	0
Other comprehensive income/(loss) retained in AOCI	7	(1)
Total before tax impact	7	(1)
Tax impact	0	0
Balance at the end of the period	(28)	(1)
Net Investment Hedges
Changes in AOCI
Balance at the beginning of the period	(1,137)	(166)
Other comprehensive income/(loss) retained in AOCI	15	133
Total before tax impact	15	133
Income tax on amounts retained in AOCI		0
Tax impact	0	0
Balance at the end of the period	(1,122)	(33)
Cumulative Translation Adjustment
Changes in AOCI
Balance at the beginning of the period	4,348	56
Other comprehensive income/(loss) retained in AOCI	(57)	(691)
Total before tax impact	(57)	(691)
Tax impact	0	0
Balance at the end of the period	4,291	(635)
Equity Investees
Changes in AOCI
Balance at the beginning of the period	5	(5)
Other comprehensive income/(loss) retained in AOCI	0	0
Total before tax impact	0	0
Income tax on amounts retained in AOCI	0	0
Tax impact	0	0
Balance at the end of the period	5	(5)
Pension and OPEB Adjustment
Changes in AOCI
Balance at the beginning of the period	218	(84)
Other comprehensive loss/(income) reclassified to earnings	(5)	(3)
Total before tax impact	(5)	(3)
Income tax on amounts reclassified to earnings	1	1
Tax impact	1	1
Balance at the end of the period	$ 214	$ (86)