INCOME TAXES - Schedule of Income Tax Rate Reconciliation (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
INCOME TAX RATE RECONCILIATION
Earnings before income taxes	$ 7,299	$ 7,879	$ 4,542
Canadian federal statutory income tax rate	15.00%	15.00%	15.00%
Expected federal taxes at statutory rate	$ 1,095	$ 1,182	$ 681
Increase/(decrease) resulting from:
Provincial and state income taxes	183	411	108
Foreign and other statutory rate differentials	340	187	295
Effects of rate-regulated accounting	(192)	(106)	(122)
Write-off of regulatory deferrals	4	115	0
Part VI.1 tax, net of federal Part I deduction	73	66	76
US minimum tax	148	100	107
Non-taxable portion of gain on sale of investment	(147)	0	0
Valuation allowance	(2)	(12)	6
Accounting impairment of non-deductible goodwill	148	0	370
Noncontrolling interests	(30)	19	9
Investment and production tax credits	(23)	(47)	0
Other	71	(94)	74
Income tax expense	$ 1,668	$ 1,821	$ 1,604
Effective income tax rate (as a percent)	22.90%	23.10%	35.30%