Value of input used to measure net derivative asset (liability).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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-Publisher FASB
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-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258

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Fair Value Measurements (Quantitative Level 3 Fair Value Disclosure) (Details) $ in Millions	Dec. 31, 2019 USD ($) $ / MWh $ / MMBTU	Dec. 31, 2018 USD ($) $ / MWh $ / MMBTU	Dec. 31, 2017 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ (102)	$ (113)	$ (114)
Duke Energy Ohio \| FTR price – per MWh \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ 4	$ 6
Duke Energy Ohio \| FTR price – per MWh \| Minimum \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	0.59	1.19
Duke Energy Ohio \| FTR price – per MWh \| Maximum \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	3.47	4.59
Duke Energy Ohio \| FTR price – per MWh \| Weighted Average [Member] \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	2.07
Duke Energy Indiana
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ 11	$ 22	27
Duke Energy Indiana \| FTR price – per MWh \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ 11	$ 22
Duke Energy Indiana \| FTR price – per MWh \| Minimum \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	(0.66)	(2.07)
Duke Energy Indiana \| FTR price – per MWh \| Maximum \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	9.24	8.27
Duke Energy Indiana \| FTR price – per MWh \| Weighted Average [Member] \| RTO auction pricing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MWh	1.15
Piedmont
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ (117)	$ (141)	$ (142)
Piedmont \| Forward natural gas curves – price per MMBtu \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Net derivative asset (liability) \| $	$ (117)	$ (141)
Piedmont \| Forward natural gas curves – price per MMBtu \| Minimum \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MMBTU	1.59	1.87
Piedmont \| Forward natural gas curves – price per MMBtu \| Maximum \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MMBTU	2.46	2.95
Piedmont \| Forward natural gas curves – price per MMBtu \| Weighted Average [Member] \| Discounted cash flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input measurement (in usd per MWh and usd per MMBtu) \| $ / MMBTU	1.91