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Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Mcf in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) GWh Mcf	Dec. 31, 2017 USD ($) GWh Mcf	Dec. 31, 2016 USD ($)	Aug. 31, 2016 USD ($)
Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 2,644	$ 1,587
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	923	660
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 1,721	$ 927
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	15,286	34
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	739	770
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 422	$ 660
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	194
Piedmont Natural Gas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Loss on Interest Rate Derivative Instruments Not Designated as Hedging Instruments			$ 190
Piedmont Natural Gas [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount				$ 1,400
Duke Energy Carolinas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	300	400
Duke Energy Carolinas [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 300	$ 400
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	121	105
Progress Energy [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 1,200	$ 500
Progress Energy [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 1,200	$ 500
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	169	183
Duke Energy Progress [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 650	$ 250
Duke Energy Progress [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 650	$ 250
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	166	133
Duke Energy Florida [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 550	$ 250
Duke Energy Florida [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 550	$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	3	50
Duke Energy Ohio [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 27	$ 27
Duke Energy Ohio [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 27	$ 27
Duke Energy Ohio [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	1,786
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Notional amount, energy measure, in gigawatt-hours | GWh	13,500	34
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	1	2
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Notional amount, volume in millions of decatherms | Mcf	448	480

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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+ References

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- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

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- Definition

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+ References

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- Definition

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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