Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	$ 61	$ 25
Location and fair value amounts of derivatives liabilities	324	300
Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	48	24
Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	13	1
Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	64	118
Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	260	182
Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	43	18
Location and fair value amounts of derivatives liabilities	251	223
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	18	6
Location and fair value amounts of derivatives liabilities	73	53
Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		1
Location and fair value amounts of derivatives liabilities		24
Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	14
Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	70
Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	15	19
Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	48	21
Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	30	17
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	13	1
Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	30	67
Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	137	156
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	18	6
Not Designated as Hedging Instruments | Interest Rate Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	5	8
Not Designated as Hedging Instruments | Interest Rate Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	5	5
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		1
Not Designated as Hedging Instruments | Equity Securities Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities		24
Duke Energy Carolinas
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	20
Location and fair value amounts of derivatives liabilities	20	49
Duke Energy Carolinas | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	14
Duke Energy Carolinas | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6
Duke Energy Carolinas | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	17	39
Duke Energy Carolinas | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	3	10
Duke Energy Carolinas | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	20
Location and fair value amounts of derivatives liabilities	16	43
Duke Energy Carolinas | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	0
Location and fair value amounts of derivatives liabilities	4	6
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	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 assets	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 liabilities	13	33
Duke Energy Carolinas | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	3	10
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 assets	0
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 liabilities	4	6
Progress Energy
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	33	7
Location and fair value amounts of derivatives liabilities	29	88
Progress Energy | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	27	7
Progress Energy | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6
Progress Energy | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	2	51
Progress Energy | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	27	37
Progress Energy | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	15
Location and fair value amounts of derivatives liabilities	29	63
Progress Energy | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	18	6
Location and fair value amounts of derivatives liabilities		1
Progress Energy | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		1
Location and fair value amounts of derivatives liabilities		24
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	9
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	2	26
Progress Energy | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	27	37
Progress Energy | Not Designated as Hedging Instruments | Interest Rate Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	18	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 liabilities		1
Progress Energy | Not Designated as Hedging Instruments | Equity Securities Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		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 liabilities		24
Duke Energy Progress
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	33
Location and fair value amounts of derivatives liabilities	14	49
Duke Energy Progress | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	27
Duke Energy Progress | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6
Duke Energy Progress | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	2	27
Duke Energy Progress | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	12	22
Duke Energy Progress | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	15
Location and fair value amounts of derivatives liabilities	14	48
Duke Energy Progress | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	18
Location and fair value amounts of derivatives liabilities		1
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	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 assets	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 liabilities	2	26
Duke Energy Progress | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	12	22
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 assets	18
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 liabilities		1
Duke Energy Florida
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		7
Location and fair value amounts of derivatives liabilities		24
Duke Energy Florida | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		7
Duke Energy Florida | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	0	24
Duke Energy Florida | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	0
Duke Energy Florida | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		6
Duke Energy Florida | Equity Securities Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		1
Location and fair value amounts of derivatives liabilities		24
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 assets		6
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 assets		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 liabilities		24
Duke Energy Ohio
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	4
Location and fair value amounts of derivatives liabilities	6	6
Duke Energy Ohio | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	3
Duke Energy Ohio | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		1
Duke Energy Ohio | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	1	1
Duke Energy Ohio | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	5	5
Duke Energy Ohio | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	4
Duke Energy Ohio | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	6	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 assets	1	3
Duke Energy Ohio | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets		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 liabilities	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 liabilities	5	5
Duke Energy Indiana
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6	13
Location and fair value amounts of derivatives liabilities	1	1
Duke Energy Indiana | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6	13
Duke Energy Indiana | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	1	1
Duke Energy Indiana | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	0
Duke Energy Indiana | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	6	13
Location and fair value amounts of derivatives liabilities	1	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 assets	6	13
Duke Energy Indiana | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	1	1
Piedmont
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	1
Location and fair value amounts of derivatives liabilities	122	117
Piedmont | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	1
Piedmont | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	15	7
Piedmont | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	107	110
Piedmont | Commodity Contracts
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	1
Location and fair value amounts of derivatives liabilities	122	117
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Assets
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives assets	1	1
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Current Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	15	7
Piedmont | Not Designated as Hedging Instruments | Commodity Contracts | Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives liabilities	$ 107	$ 110