Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ 76
Cumulative Change in Accounting Principle	146
Write-Offs	58
Credit Loss Expense	75
Other Adjustments	48
Balance at December 31, 2020	146
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	10
Cumulative Change in Accounting Principle	23
Write-Offs	13
Credit Loss Expense	13
Other Adjustments	12
Balance at December 31, 2020	23
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	16
Cumulative Change in Accounting Principle	37
Write-Offs	23
Credit Loss Expense	29
Other Adjustments	13
Balance at December 31, 2020	37
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	8
Cumulative Change in Accounting Principle	23
Write-Offs	8
Credit Loss Expense	9
Other Adjustments	13
Balance at December 31, 2020	23
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	7
Cumulative Change in Accounting Principle	14
Write-Offs	14
Credit Loss Expense	20
Balance at December 31, 2020	14
Duke Energy Ohio
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	4
Cumulative Change in Accounting Principle	4
Balance at December 31, 2020	4
Duke Energy Indiana
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	3
Cumulative Change in Accounting Principle	3
Balance at December 31, 2020	3
Piedmont
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	6
Cumulative Change in Accounting Principle	12
Write-Offs	6
Credit Loss Expense	11
Balance at December 31, 2020	12
Cumulative Change in Accounting Principle
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	5
Cumulative Change in Accounting Principle	5
Cumulative Change in Accounting Principle | Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	1
Cumulative Change in Accounting Principle	1
Cumulative Change in Accounting Principle | Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	2
Cumulative Change in Accounting Principle	2
Cumulative Change in Accounting Principle | Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	1
Cumulative Change in Accounting Principle	1
Cumulative Change in Accounting Principle | Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	1
Cumulative Change in Accounting Principle	1
Cumulative Change in Accounting Principle | Piedmont
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	1
Cumulative Change in Accounting Principle	$ 1