INCOME TAXES - Deferred Income Taxes (Details) - CAD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Deferred income tax liabilities
Property, plant and equipment	$ (9,096)	$ (8,721)
Investments	(7,099)	(6,097)
Regulatory assets	(1,291)	(1,245)
Pension and OPEB plans	(30)	0
Other	(46)	(208)
Total deferred income tax liabilities	(17,562)	(16,271)
Deferred income tax assets
Financial instruments	456	315
Pension and OPEB plans	0	110
Loss carryforwards	2,259	3,081
Other	1,753	1,648
Total deferred income tax assets	4,468	5,154
Less valuation allowance	(215)	(84)
Total deferred income tax assets, net	4,253	5,070
Net deferred income tax liabilities	(13,309)	(11,201)
Deferred income taxes	472	488
Total deferred income tax liabilities	(13,781)	(11,689)
Operating loss carryforwards that do not expire	7,900	7,500
Foreign subsidiaries' undistributed earnings on which deferred income taxes has not been provided	8,000	4,300
Canada
Deferred income tax assets
Benefit of unused tax loss carryforwards recognized	2,100	1,900
US
Deferred income tax assets
Benefit of unused tax loss carryforwards recognized	8,100	11,000
Operating loss carryforwards that expire	$ 200	$ 3,500