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Regulatory Matters (Narrative) (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Jan. 22, 2021
Oct. 26, 2020
Dec. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Public Utilities, General Disclosures [Line Items]            
Impairment charges       $ 984 $ (8) $ 402
Duke Energy Ohio            
Public Utilities, General Disclosures [Line Items]            
Limit of total capital     30.00% 30.00%    
Duke Energy Kentucky            
Public Utilities, General Disclosures [Line Items]            
Required minimum equity capital structure     35.00% 35.00%    
Duke Energy Carolinas            
Public Utilities, General Disclosures [Line Items]            
Impairment charges       $ 476 17 192
Duke Energy Carolinas | North Carolina Utilities Commission            
Public Utilities, General Disclosures [Line Items]            
Requested rate increase (decrease), amended, amount   $ 287        
Duke Energy Carolinas | CCR Settlement Agreement            
Public Utilities, General Disclosures [Line Items]            
Impairment charges     $ 454      
Reversal of regulated electric operating revenues     50      
Duke Energy Progress            
Public Utilities, General Disclosures [Line Items]            
Impairment charges       $ 499 $ 12 $ 33
Duke Energy Progress | North Carolina Utilities Commission            
Public Utilities, General Disclosures [Line Items]            
Requested rate increase (decrease), amended, amount   $ 920        
Duke Energy Progress | CCR Settlement Agreement            
Public Utilities, General Disclosures [Line Items]            
Impairment charges     494      
Reversal of regulated electric operating revenues     $ 102      
Duke Energy Carolinas and Duke Energy Progress | CCR Settlement Agreement | Subsequent Event            
Public Utilities, General Disclosures [Line Items]            
Recovery costs not sought $ 1,000          
Recovery costs amortization period 5 years          
Equity return on deferred coal ash cost future cases 1.50%          
Duke Energy Carolinas and Duke Energy Progress | CCR Settlement Agreement | NCUC | Subsequent Event            
Public Utilities, General Disclosures [Line Items]            
Requested capital structure, percentage 48.00%          
Requested debt structure, percentage 52.00%