Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 25	$ 57
Location and fair value amounts of derivatives (Liability)	300	242
Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	24	38
Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	19
Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	118	68
Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	182	174
Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	18	39
Location and fair value amounts of derivatives (Liability)	223	191
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	18
Location and fair value amounts of derivatives (Liability)	53	51
Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	19	12
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	21	6
Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	35
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	4
Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	67	33
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	156	158
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	2
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	23
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5	10
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		12
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Carolinas
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	49	33
Duke Energy Carolinas | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Carolinas | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Carolinas | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	39	23
Duke Energy Carolinas | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	10	10
Duke Energy Carolinas | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Location and fair value amounts of derivatives (Liability)	43	24
Duke Energy Carolinas | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	9
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)		2
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)		1
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)	33	14
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)	10	10
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)	6	9
Progress Energy
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	4
Location and fair value amounts of derivatives (Liability)	88	44
Progress Energy | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Progress Energy | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	51	23
Progress Energy | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	21
Progress Energy | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	63	25
Progress Energy | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Location and fair value amounts of derivatives (Liability)	1	19
Progress Energy | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	26	10
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	15
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)	6
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)	1	13
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Progress Energy | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Progress Energy | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Progress
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	49	27
Duke Energy Progress | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		2
Duke Energy Progress | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	27	16
Duke Energy Progress | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	22	11
Duke Energy Progress | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		4
Location and fair value amounts of derivatives (Liability)	48	11
Duke Energy Progress | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	16
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)		2
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)		2
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)	26	5
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)	22	6
Duke Energy Progress | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	11
Duke Energy Progress | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		5
Duke Energy Florida
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Location and fair value amounts of derivatives (Liability)	24	9
Duke Energy Florida | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7
Duke Energy Florida | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24	8
Duke Energy Florida | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Florida | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
Duke Energy Florida | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Location and fair value amounts of derivatives (Liability)		3
Duke Energy Florida | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Florida | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		6
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)	6
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)		2
Duke Energy Florida | Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		1
Duke Energy Florida | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
Duke Energy Florida | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	24
Duke Energy Ohio
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Location and fair value amounts of derivatives (Liability)	6	5
Duke Energy Ohio | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3	6
Duke Energy Ohio | Noncurrent 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)	5	4
Duke Energy Ohio | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	6
Duke Energy Ohio | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	5
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	6
Duke Energy Ohio | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent 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)	5	4
Duke Energy Indiana
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	23
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)	13	23
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)	13	23
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)	13	23
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	3
Location and fair value amounts of derivatives (Liability)	117	141
Piedmont | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Piedmont | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	8
Piedmont | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	110	133
Piedmont | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Location and fair value amounts of derivatives (Liability)	117	141
Piedmont | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		0
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		0
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	7	8
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 110	$ 133