Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 123	$ 102	$ 146	$ 76
Cumulative Change in Accounting Principle	123	133	123	133
Write-Offs	(13)	12	(39)	(7)
Credit Loss Expense	11	(9)	40	24
Other Adjustments	2	28	(24)	35
Ending balance	123	133	123	133
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	42	14	23	10
Cumulative Change in Accounting Principle	42	22	42	22
Write-Offs	(3)	(2)	(10)	(8)
Credit Loss Expense	4		20	9
Other Adjustments	(1)	10	9	10
Ending balance	42	22	42	22
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	36	29	37	16
Cumulative Change in Accounting Principle	36	37	36	37
Write-Offs	(6)	15	(20)	8
Credit Loss Expense	6	(16)	19	2
Other Adjustments		9		9
Ending balance	36	37	36	37
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	21	14	23	8
Cumulative Change in Accounting Principle	21	21	21	21
Write-Offs	(3)	13	(11)	8
Credit Loss Expense	3	(15)	9	(5)
Other Adjustments		9		9
Ending balance	21	21	21	21
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	16	14	14	7
Cumulative Change in Accounting Principle	16	16	16	16
Write-Offs	(3)	2	(9)
Credit Loss Expense	3		10	8
Other Adjustments			1
Ending balance	16	16	16	16
Duke Energy Ohio
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	4	5	4	4
Cumulative Change in Accounting Principle	4	5	4	5
Credit Loss Expense				1
Ending balance	4	5	4	5
Duke Energy Indiana
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3	3	3	3
Cumulative Change in Accounting Principle	3	3	3	3
Ending balance	3	3	3	3
Piedmont
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	13	6	12	6
Cumulative Change in Accounting Principle	15	9	15	9
Write-Offs	(4)		(7)	(5)
Credit Loss Expense	2	3	6	7
Other Adjustments	4		4
Ending balance	$ 15	$ 9	$ 15	9
Cumulative Change in Accounting Principle
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				5
Cumulative Change in Accounting Principle
Cumulative Change in Accounting Principle | Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				1
Cumulative Change in Accounting Principle
Cumulative Change in Accounting Principle | Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				2
Cumulative Change in Accounting Principle
Cumulative Change in Accounting Principle | Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				1
Cumulative Change in Accounting Principle
Cumulative Change in Accounting Principle | Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				1
Cumulative Change in Accounting Principle
Cumulative Change in Accounting Principle | Piedmont
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance				$ 1
Cumulative Change in Accounting Principle