Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 206	$ 61
Location and fair value amounts of derivatives (Liability)	349	324
Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	192	48
Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14	13
Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	57	64
Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	292	260
Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	46	43
Location and fair value amounts of derivatives (Liability)	301	251
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	160	18
Location and fair value amounts of derivatives (Liability)	48	73
Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	32	30
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14	13
Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	30
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	154	137
Not Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	129	18
Not Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	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)	19	14
Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	109	70
Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	31
Designated as Hedging Instruments | Interest Rate Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	15	15
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	48
Duke Energy Carolinas
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	62	20
Location and fair value amounts of derivatives (Liability)		20
Duke Energy Carolinas | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	55	14
Duke Energy Carolinas | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	6
Duke Energy Carolinas | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		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)	24	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 (Asset)	38
Location and fair value amounts of derivatives (Liability)		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)	17	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)	7	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 assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	38
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)		4
Progress Energy
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	103	33
Location and fair value amounts of derivatives (Liability)	28	29
Progress Energy | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	96	27
Progress Energy | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	6
Progress Energy | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3	2
Progress Energy | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	27
Progress Energy | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	19	15
Location and fair value amounts of derivatives (Liability)	25	29
Progress Energy | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	84	18
Location and fair value amounts of derivatives (Liability)	3
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	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)	7	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)	25	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)	84	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)	3
Duke Energy Progress
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	100	33
Location and fair value amounts of derivatives (Liability)	9	14
Duke Energy Progress | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	93	27
Duke Energy Progress | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	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)	9	12
Duke Energy Progress | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	19	15
Location and fair value amounts of derivatives (Liability)	9	14
Duke Energy Progress | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	81	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)	12	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)	7	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)	9	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)	81	18
Duke Energy Florida
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	3
Duke Energy Florida | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Duke Energy Florida | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3
Duke Energy Florida | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	3
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
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)	3
Duke Energy Ohio
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		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)		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)		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)		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)	2	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)	2	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)	2	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)	2	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)	1	1
Location and fair value amounts of derivatives (Liability)	148	122
Piedmont | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	1
Piedmont | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	15
Piedmont | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	129	107
Piedmont | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	1
Location and fair value amounts of derivatives (Liability)	148	122
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	1
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	15
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 129	$ 107