Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ 76
Cumulative Change in Accounting Principle	89
Write-Offs	(10)
Credit Loss Expense	18
Balance at March 31, 2020	89
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	10
Cumulative Change in Accounting Principle	11
Write-Offs	(3)
Credit Loss Expense	3
Balance at March 31, 2020	11
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	16
Cumulative Change in Accounting Principle	20
Write-Offs	(4)
Credit Loss Expense	6
Balance at March 31, 2020	20
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	8
Cumulative Change in Accounting Principle	9
Write-Offs	(2)
Credit Loss Expense	2
Balance at March 31, 2020	9
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	7
Cumulative Change in Accounting Principle	11
Write-Offs	(2)
Credit Loss Expense	5
Balance at March 31, 2020	11
Duke Energy Ohio
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	4
Cumulative Change in Accounting Principle	5
Credit Loss Expense	1
Balance at March 31, 2020	5
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 March 31, 2020	3
Piedmont Natural Gas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	6
Cumulative Change in Accounting Principle	9
Write-Offs	(1)
Credit Loss Expense	3
Balance at March 31, 2020	9
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 Natural Gas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	1
Cumulative Change in Accounting Principle	$ 1