XML 117 R89.htm IDEA: XBRL DOCUMENT v3.20.4
Revenue (Details) - CAD ($)
$ in Millions
 12 Months Ended
Oct. 01, 2019
Dec. 31, 2020
Dec. 31, 2019
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   $ 2 $ 0
Canadian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   13  
Australian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   2,594  
Alberta Thermal      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   336  
Hydro      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   31  
Wind and Solar      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   13  
Later than one year | Hydro      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   8  
Second to fifth years inclusive | Australian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   $ 203  
Genesee 3      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Ownership percentage sold     50.00%
Minimum      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Contracts for sale of byproducts of coal combustion, term   1 year  
Minimum | Canadian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   $ 4  
Minimum | Australian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   100  
Minimum | Wind and Solar      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   2  
Minimum | More than five years      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   2  
Minimum | 2023 | Alberta Thermal      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   5  
Minimum | Annually thereafter | Alberta Thermal      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   $ 40  
Maximum      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Contracts for sale of byproducts of coal combustion, term   3 years  
Maximum | Canadian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   $ 5  
Maximum | Australian Gas      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   126  
Maximum | Wind and Solar      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Performance obligations satisfied   5  
Maximum | More than five years      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   3  
Maximum | 2023 | Alberta Thermal      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   10  
Maximum | Annually thereafter | Alberta Thermal      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Transaction price allocated to remaining performance obligations   $ 45  
Keephills 3      
Disclosure of disaggregation of revenue from contracts with customers [line items]      
Proportion of ownership interest in joint operation 50.00%   50.00%