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Employee Benefit Plans (Employee Savings Plans) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]      
Matching contribution percentage 100.00%    
Eligible pay percentage 6.00%    
Additional contribution percentage for employees not participating in defined pension plans 4.00%    
Employer contributions $ 229 $ 213 $ 214
Vesting period 3 years    
Duke Energy Carolinas      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions $ 70 67 66
Progress Energy      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions 60 57 58
Duke Energy Progress      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions 39 38 38
Duke Energy Florida      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions 21 19 20
Duke Energy Ohio      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions 5 5 5
Duke Energy Indiana      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions 12 11 11
Piedmont      
Defined Benefit Plan Disclosure [Line Items]      
Employer contributions $ 11 $ 13 $ 13
Minimum | Piedmont      
Defined Benefit Plan Disclosure [Line Items]      
Additional contribution percentage for employees not participating in defined pension plans 3.00%    
Maximum | Piedmont      
Defined Benefit Plan Disclosure [Line Items]      
Additional contribution percentage for employees not participating in defined pension plans 5.00%