Derivatives and Hedging (Notional Amounts of Derivative Instruments) (Details) Bcf in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) GWh Bcf	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($) GWh Bcf
Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 1,677		$ 2,324
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	750		497
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 927		$ 1,827
Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | GWh	147		70
Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	890		398
Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 750		$ 497
Piedmont Natural Gas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Gain (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]
Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments	$ (190)
Notional Amount		$ 1,400
Piedmont Natural Gas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	529
Duke Energy Carolinas [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 400		400
Duke Energy Carolinas [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 400		$ 400
Duke Energy Carolinas [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	91		66
Progress Energy [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 500		$ 500
Progress Energy [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 500		$ 500
Progress Energy [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	269		332
Duke Energy Progress [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Progress [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Progress [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	118		117
Duke Energy Florida [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Florida [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 250		$ 250
Duke Energy Florida [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	151		215
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]
Derivative, Nonmonetary Notional Amount | GWh			34
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Electricity [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | GWh	147		36
Duke Energy Indiana [Member] | Commodity Contracts [Member] | Natural Gas [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	1
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 300
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | 4YearInterestRateContract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	81
Commercial Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | 18YearInterestRateContract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional Amount	$ 219