COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - CAD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Changes in AOCI
Balance at the beginning of the period	$ 63,398
Other comprehensive income/(loss) retained in AOCI	(947)	$ 1,732
Total before tax impact	(934)	1,866
Income tax on amounts retained in AOCI	(23)	(202)
Income tax on amounts reclassified to earnings	(2)	(30)
Tax impact	(25)	(232)
Balance at the end of the period	64,038	64,537
Interest rate contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	23	142
Foreign exchange contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings		(4)
Commodity contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	(1)
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	2,561	538
Cash Flow Hedges
Changes in AOCI
Balance at the beginning of the period	121	(897)
Other comprehensive income/(loss) retained in AOCI	126	854
Total before tax impact	149	994
Income tax on amounts retained in AOCI	(23)	(202)
Income tax on amounts reclassified to earnings	(4)	(31)
Tax impact	(27)	(233)
Balance at the end of the period	243	(136)
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	23	142
Cash Flow Hedges | Foreign exchange contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings		(4)
Cash Flow Hedges | Commodity contracts
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	(1)
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	9	(5)
Total before tax impact	9	(5)
Tax impact	0	0
Balance at the end of the period	(26)	(5)
Net Investment Hedges
Changes in AOCI
Balance at the beginning of the period	(1,137)	(166)
Other comprehensive income/(loss) retained in AOCI	400	(253)
Total before tax impact	400	(253)
Income tax on amounts retained in AOCI		0
Tax impact	0	0
Balance at the end of the period	(737)	(419)
Cumulative Translation Adjustment
Changes in AOCI
Balance at the beginning of the period	4,348	56
Other comprehensive income/(loss) retained in AOCI	(1,482)	1,136
Total before tax impact	(1,482)	1,136
Tax impact	0	0
Balance at the end of the period	2,866	1,192
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	(10)	(6)
Total before tax impact	(10)	(6)
Income tax on amounts reclassified to earnings	2	1
Tax impact	2	1
Balance at the end of the period	$ 210	$ (89)