v3.25.4
Long-term debt - Summary of Long-Term Debt (Details)
$ in Millions, $ in Millions
Dec. 31, 2025
CAD ($)
Dec. 31, 2025
USD ($)
Jun. 30, 2025
CAD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2024
CAD ($)
Dec. 31, 2024
USD ($)
Disclosure of detailed information about borrowings [line items]            
Total long-term debt $ 34,904       $ 32,835  
Forward Starting Interest Rate Swap            
Disclosure of detailed information about borrowings [line items]            
Notional amount         1,080 $ 800
Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt 37,070       36,862  
Net Unamortised Discount (Premium)            
Disclosure of detailed information about borrowings [line items]            
Total debt 8       29  
Unamortized debt issuance costs            
Disclosure of detailed information about borrowings [line items]            
Total debt 163       132  
Supplier finance arrangements due within one year            
Disclosure of detailed information about borrowings [line items]            
Total debt 70       73  
Long-term debt            
Disclosure of detailed information about borrowings [line items]            
Total debt 1,925       3,793  
1997 trust indenture | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt 17,502       20,273  
1997 trust indenture | Trade receivables | Interest rate swap contract            
Disclosure of detailed information about borrowings [line items]            
Notional amount 1,995       1,300  
1997 trust indenture | Trade receivables | Forward Starting Interest Rate Swap | 2028            
Disclosure of detailed information about borrowings [line items]            
Notional amount $ 525       525  
1997 trust indenture | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 4.42% 4.42%        
1976 trust indenture | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 975       975  
1976 trust indenture | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 9.38% 9.38%        
2016 U.S. trust indenture            
Disclosure of detailed information about borrowings [line items]            
Notional amount   $ 5,706       $ 6,550
2016 U.S. trust indenture | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 7,840       9,445  
2016 U.S. trust indenture | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 4.37% 4.37%        
1996 trust indenture (subordinated) | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 275       275  
1996 trust indenture (subordinated) | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 8.21% 8.21%        
Subordinated 2025 Canadian Trust Indenture | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 1,250       0  
Subordinated 2025 Canadian Trust Indenture | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 5.63% 5.63%        
Subordinated 2025 U.S. Trust Indenture            
Disclosure of detailed information about borrowings [line items]            
Borrowings $ 2,250          
Subordinated 2025 U.S. Trust Indenture | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 3,088       0  
Subordinated 2025 U.S. Trust Indenture | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 6.94% 6.94%        
Lease liabilities | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 4,309       4,591  
Lease liabilities | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 4.24% 4.24%        
Bell Mobility trade loan            
Disclosure of detailed information about borrowings [line items]            
Borrowings, principal amount, repurchased   $ 600        
Bell Mobility trade loan | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 0       863  
Unsecured committed term loan facility            
Disclosure of detailed information about borrowings [line items]            
Borrowings   $ 487        
Unsecured committed term loan facility | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 668       0  
Unsecured committed term loan facility | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 4.40% 4.40%        
Unsecured term loan facility            
Disclosure of detailed information about borrowings [line items]            
Borrowings   $ 500        
Unsecured term loan facility | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 686       0  
Unsecured term loan facility | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 5.38% 5.38%        
Supplier finance arrangements | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 165       197  
Supplier finance arrangements | Weighted average            
Disclosure of detailed information about borrowings [line items]            
Weighted average interest rate at December 31, 2025 4.00% 4.00%        
Other | Trade receivables            
Disclosure of detailed information about borrowings [line items]            
Total debt $ 312       $ 243  
Total non-committed credit facilities | Bell Mobility Inc.            
Disclosure of detailed information about borrowings [line items]            
Borrowings, principal amount, repurchased     $ 819 $ 600