COMPONENTS OF ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Components of accumulated other comprehensive loss
Balance at beginning of year	$ 63,368	$ 64,363
Other comprehensive income/(loss) retained in AOCI	4,816	298	$ (1,522)
Changes in AOCI
Other	16	0
Other comprehensive loss/(income) reclassified to earnings	5,004	564	(1,249)
Income tax on amounts retained in AOCI	(349)	(187)	182
Income tax on amounts reclassified to earnings	(39)	(72)	(62)
Tax impact	(388)	(259)	120
Balance at end of year	63,398	63,368	64,363
Interest rate contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	186	296	253
Commodity contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs		1
Forward exchange contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	(4)	5	5
Other contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	4	2	(2)
Equity investment disposal
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs		(66)
Cash Flow Hedges
Components of accumulated other comprehensive loss
Balance at beginning of year	(897)	(1,326)	(1,073)
Other comprehensive income/(loss) retained in AOCI	1,125	238	(591)
Changes in AOCI
Other	0	17
Other comprehensive loss/(income) reclassified to earnings	1,311	559	(335)
Income tax on amounts retained in AOCI	(250)	(61)	140
Income tax on amounts reclassified to earnings	(43)	(69)	(58)
Tax impact	(293)	(130)	82
Balance at end of year	121	(897)	(1,326)
Cash Flow Hedges | Interest rate contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	186	296	253
Cash Flow Hedges | Commodity contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs		1
Cash Flow Hedges | Forward exchange contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	(4)	5	5
Cash Flow Hedges | Other contracts
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	4	2	(2)
Cash Flow Hedges | Equity investment disposal
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs		0
Excluded Components of Fair Value Hedges
Components of accumulated other comprehensive loss
Balance at beginning of year	0	5	0
Other comprehensive income/(loss) retained in AOCI	(35)	(5)	5
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	(35)	(5)	5
Income tax on amounts retained in AOCI	0	0	0
Income tax on amounts reclassified to earnings	0	0	0
Tax impact	0	0	0
Balance at end of year	(35)	0	5
Net Investment Hedges
Components of accumulated other comprehensive loss
Balance at beginning of year	(166)	(215)	(317)
Other comprehensive income/(loss) retained in AOCI	(971)	49	115
Changes in AOCI
Other comprehensive loss/(income) reclassified to earnings	(971)	49	115
Income tax on amounts retained in AOCI	0	0	(13)
Income tax on amounts reclassified to earnings	0	0
Tax impact	0	0	(13)
Balance at end of year	(1,137)	(166)	(215)
Cumulative Translation Adjustment
Components of accumulated other comprehensive loss
Balance at beginning of year	56	568	1,396
Other comprehensive income/(loss) retained in AOCI	4,292	(492)	(828)
Changes in AOCI
Other	0	(20)
Other comprehensive loss/(income) reclassified to earnings	4,292	(512)	(828)
Income tax on amounts retained in AOCI	0	0
Income tax on amounts reclassified to earnings	0	0
Tax impact	0	0
Balance at end of year	4,348	56	568
Equity Investees
Components of accumulated other comprehensive loss
Balance at beginning of year	(5)	66	67
Other comprehensive income/(loss) retained in AOCI	(6)	(12)	(2)
Changes in AOCI
Other	16	3
Other comprehensive loss/(income) reclassified to earnings	10	(75)	(2)
Income tax on amounts retained in AOCI	0	0	1
Income tax on amounts reclassified to earnings	0	4
Tax impact	0	4	1
Balance at end of year	5	(5)	66
Equity Investees | Equity investment disposal
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs		66
Pension and OPEB Adjustment
Components of accumulated other comprehensive loss
Balance at beginning of year	(84)	(499)	(345)
Other comprehensive income/(loss) retained in AOCI	411	520	(221)
Changes in AOCI
Amortization of pension and OPEB actuarial loss and prior service costs	(14)	28	17
Other comprehensive loss/(income) reclassified to earnings	397	548	(204)
Income tax on amounts retained in AOCI	(99)	(126)	54
Income tax on amounts reclassified to earnings	4	(7)	(4)
Tax impact	(95)	(133)	50
Balance at end of year	218	(84)	(499)
Total
Components of accumulated other comprehensive loss
Balance at beginning of year	(1,096)	(1,401)	(272)
Changes in AOCI
Balance at end of year	$ 3,520	$ (1,096)	$ (1,401)