Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 282	$ 61
Location and fair value amounts of derivatives (Liability)	423	324
Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	215	48
Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	67	13
Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	91	64
Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	332	260
Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	230	43
Location and fair value amounts of derivatives (Liability)	322	251
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	52	18
Location and fair value amounts of derivatives (Liability)	101	73
Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	163	30
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	67	13
Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	27	30
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	139	137
Not Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	52	18
Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	21	5
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	5
Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	29	14
Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	127	70
Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	14	15
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	62	48
Duke Energy Carolinas
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	107	20
Location and fair value amounts of derivatives (Liability)	7	20
Duke Energy Carolinas | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	69	14
Duke Energy Carolinas | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	38	6
Duke Energy Carolinas | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	17
Duke Energy Carolinas | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		3
Duke Energy Carolinas | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	107	20
Location and fair value amounts of derivatives (Liability)		16
Duke Energy Carolinas | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	4
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	69	14
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	38	6
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		13
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		3
Duke Energy Carolinas | Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	4
Progress Energy
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	142	33
Location and fair value amounts of derivatives (Liability)	17	29
Progress Energy | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	113	27
Progress Energy | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	29	6
Progress Energy | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	13	2
Progress Energy | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	27
Progress Energy | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	94	15
Location and fair value amounts of derivatives (Liability)	4	29
Progress Energy | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	48	18
Location and fair value amounts of derivatives (Liability)	13
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	65	9
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	29	6
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	27
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	48	18
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	13
Duke Energy Progress
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	132	33
Location and fair value amounts of derivatives (Liability)	4	14
Duke Energy Progress | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	102	27
Duke Energy Progress | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	30	6
Duke Energy Progress | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Progress | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	12
Duke Energy Progress | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	84	15
Location and fair value amounts of derivatives (Liability)	4	14
Duke Energy Progress | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	48	18
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	54	9
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	30	6
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	12
Duke Energy Progress | Not Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	48	18
Duke Energy Florida
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Location and fair value amounts of derivatives (Liability)	13
Duke Energy Florida | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Duke Energy Florida | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	13
Duke Energy Florida | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Duke Energy Florida | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	13
Duke Energy Florida | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	13
Duke Energy Ohio
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	1
Location and fair value amounts of derivatives (Liability)	5	6
Duke Energy Ohio | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	1
Duke Energy Ohio | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	5
Duke Energy Ohio | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	1
Duke Energy Ohio | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	6
Duke Energy Ohio | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	1
Duke Energy Ohio | Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	1
Duke Energy Ohio | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	5
Duke Energy Indiana
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	6
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Indiana | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	6
Duke Energy Indiana | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Indiana | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	6
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Indiana | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	6
Duke Energy Indiana | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Piedmont
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Location and fair value amounts of derivatives (Liability)	161	122
Piedmont | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Piedmont | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	15
Piedmont | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	135	107
Piedmont | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Location and fair value amounts of derivatives (Liability)	161	122
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	1
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	15
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 135	$ 107