Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ 102	$ 76
Cumulative Change in Accounting Principle	133	76
Write-Offs	12	(7)
Credit Loss Expense	(9)	24
Other Adjustments	28	35
Balance at September 30, 2020	133	133
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	14	10
Cumulative Change in Accounting Principle	22	22
Write-Offs	(2)	(8)
Credit Loss Expense		9
Other Adjustments	10	10
Balance at September 30, 2020	22	22
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	29	16
Cumulative Change in Accounting Principle	37	16
Write-Offs	15	8
Credit Loss Expense	(16)	2
Other Adjustments	9	9
Balance at September 30, 2020	37	37
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	14	8
Cumulative Change in Accounting Principle	21	8
Write-Offs	13	8
Credit Loss Expense	(15)	(5)
Other Adjustments	9	9
Balance at September 30, 2020	21	21
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	14	7
Cumulative Change in Accounting Principle	16	16
Write-Offs	2
Credit Loss Expense		8
Balance at September 30, 2020	16	16
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 September 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 September 30, 2020	3	3
Piedmont Natural Gas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	6	6
Cumulative Change in Accounting Principle	9	9
Write-Offs		(5)
Credit Loss Expense	3	7
Balance at September 30, 2020	$ 9	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