Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ 89	$ 76
Cumulative Change in Accounting Principle	102	102
Write-Offs	(9)	(19)
Other Adjustments	7	7
Credit Loss Expense	15	33
Balance at June 30, 2020	102	102
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	11	10
Cumulative Change in Accounting Principle	14	10
Write-Offs	(3)	(6)
Credit Loss Expense	6	9
Balance at June 30, 2020	14	14
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	20	16
Cumulative Change in Accounting Principle	29	29
Write-Offs	(3)	(7)
Credit Loss Expense	12	18
Balance at June 30, 2020	29	29
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	9	8
Cumulative Change in Accounting Principle	14	14
Write-Offs	(3)	(5)
Credit Loss Expense	8	10
Balance at June 30, 2020	14	14
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	11	7
Cumulative Change in Accounting Principle	14	7
Write-Offs		(2)
Credit Loss Expense	3	8
Balance at June 30, 2020	14	14
Duke Energy Ohio
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	5	4
Cumulative Change in Accounting Principle	5	4
Credit Loss Expense		1
Balance at June 30, 2020	5	5
Duke Energy Indiana
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	3	3
Cumulative Change in Accounting Principle	3	3
Balance at June 30, 2020	3	3
Piedmont Natural Gas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	9	6
Cumulative Change in Accounting Principle	6	6
Write-Offs	(4)	(5)
Credit Loss Expense	1	4
Balance at June 30, 2020	$ 6	6
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