v3.25.4
Equity Capital and Earnings Per Share - Preferred Shares and Other Equity Instruments (Detail) - CAD ($)
$ / shares in Units, shares in Millions, $ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of classes of share capital [Line Items]    
Face amount $ 513,010 $ 499,021
LRCN, Series 1 | On June 19, 2026 and every five years thereafter until June 19, 2076    
Disclosure of classes of share capital [Line Items]    
Borrowings, adjustment to interest rate basis 2.839%  
Other equity instruments | LRCN, Series 1    
Disclosure of classes of share capital [Line Items]    
Limited recourse capital notes, annual dividend / distribution rate 3.375%  
Face amount $ 2,000  
Net amount $ 1,982 1,982
Other equity instruments | LRCN, Series 1 | Before June 18, 2026    
Disclosure of classes of share capital [Line Items]    
Borrowings, interest rate 3.375%  
Other equity instruments | LRCN, Series 2    
Disclosure of classes of share capital [Line Items]    
Limited recourse capital notes, annual dividend / distribution rate 4.10%  
Face amount $ 1,200  
Net amount $ 1,189 1,189
Other equity instruments | LRCN, Series 2 | Before March 18, 2027    
Disclosure of classes of share capital [Line Items]    
Borrowings, interest rate 4.10%  
Other equity instruments | LRCN, Series 2 | On March 19, 2027 and every five years thereafter until March 19, 2077    
Disclosure of classes of share capital [Line Items]    
Borrowings, adjustment to interest rate basis 2.704%  
Other equity instruments | LRCN, Series 3    
Disclosure of classes of share capital [Line Items]    
Limited recourse capital notes, annual dividend / distribution rate 7.117%  
Face amount $ 1,000  
Net amount $ 990 990
Borrowings, interest rate 7.117%  
Borrowings, adjustment to interest rate basis 3.95%  
Class A preferred shares, Series 2    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 4.65%  
Number of shares 14  
Face amount $ 350  
Net amount $ 344 344
Class A preferred shares, Series 3    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 4.50%  
Number of shares 12  
Face amount $ 300  
Net amount $ 294 294
Class 1 preferred shares, Series 3    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 2.348%  
Number of shares 7  
Face amount $ 163  
Net amount $ 160 160
Specified yield percentage 1.41%  
Class 1 preferred shares, Series 4    
Disclosure of classes of share capital [Line Items]    
Number of shares 1  
Face amount $ 37  
Net amount $ 36 36
Basis spread on dividend rate 1.41%  
Class 1 preferred shares, Series 4 | If redeemed on June 19, 2021    
Disclosure of classes of share capital [Line Items]    
Price per share $ 25.00  
Class 1 preferred shares, Series 4 | If redeemed after June 19, 2021    
Disclosure of classes of share capital [Line Items]    
Price per share $ 25.50  
Class 1 preferred shares, Series 9    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 5.978%  
Number of shares 10  
Face amount $ 250  
Net amount $ 244 244
Specified yield percentage 2.86%  
Class 1 preferred shares, Series 11    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 6.159%  
Number of shares 8  
Face amount $ 200  
Net amount $ 196 196
Specified yield percentage 2.61%  
Class 1 preferred shares, Series 13    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 6.35%  
Number of shares 8  
Face amount $ 200  
Net amount $ 196 196
Specified yield percentage 2.22%  
Class 1 preferred shares, Series 15    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 5.775%  
Number of shares 8  
Face amount $ 200  
Net amount $ 195 195
Specified yield percentage 2.16%  
Class 1 preferred shares, Series 17    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 5.542%  
Number of shares 14  
Face amount $ 350  
Net amount $ 343 343
Specified yield percentage 2.36%  
Class 1 preferred shares, Series 17 | After December 2024 for 5-Years    
Disclosure of classes of share capital [Line Items]    
Annual dividend rate 5.169%  
Class 1 preferred shares, Series 19    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 5.169%  
Number of shares 10  
Face amount $ 250  
Net amount $ 246 246
Specified yield percentage 2.30%  
Class 1 preferred shares, Series 25    
Disclosure of classes of share capital [Line Items]    
Preferred shares, annual dividend / distribution rate 5.942%  
Number of shares 10  
Face amount $ 250  
Net amount $ 245 245
Specified yield percentage 2.55%  
Preferred shares    
Disclosure of classes of share capital [Line Items]    
Number of shares  
Face amount $ 6,750  
Net amount $ 6,660 $ 6,660