Revenue (Reserve for Credit Losses for Trade and Other Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 147	$ 89	$ 146	$ 76
Cumulative Change in Accounting Principle	123	102	123	102
Write-Offs	(5)	(9)	(26)	(19)
Credit Loss Expense	12	15	29	33
Other Adjustments	(31)	7	(26)	7
Ending balance	123	102	123	102
Duke Energy Carolinas
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	34	11	23	10
Cumulative Change in Accounting Principle	42	14	42	14
Write-Offs	1	(3)	(7)	(6)
Credit Loss Expense	6	6	16	9
Other Adjustments	1		10
Ending balance	42	14	42	14
Progress Energy
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	37	20	37	16
Cumulative Change in Accounting Principle	36	29	36	29
Write-Offs	(4)	(3)	(14)	(7)
Credit Loss Expense	6	12	13	18
Other Adjustments	(3)
Ending balance	36	29	36	29
Duke Energy Progress
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	23	9	23	8
Cumulative Change in Accounting Principle	21	14	21	14
Write-Offs	(3)	(3)	(8)	(5)
Credit Loss Expense	4	8	6	10
Other Adjustments	(3)
Ending balance	21	14	21	14
Duke Energy Florida
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	15	11	14	7
Cumulative Change in Accounting Principle	16	14	16	14
Write-Offs	(1)		(6)	(2)
Credit Loss Expense	2	3	7	8
Other Adjustments			1
Ending balance	16	14	16	14
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	14	9	12	6
Cumulative Change in Accounting Principle	13	6	13	6
Write-Offs	(2)	(4)	(3)	(5)
Credit Loss Expense	1	1	4	4
Ending balance	$ 13	$ 6	$ 13	6
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