Fair Value Of Financial Assets and Liabilities (Quantitative Level 3 Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ (43)	$ (53)
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	10.36	9.99
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	3.47	2.33
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(4)	(23)
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	48.34	48.69
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	25.79	25.83
Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	15	11
Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	10.86	39.22
Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	(1.53)	23.63
Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	5	(8)
Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	54.19	77.96
Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	26.20	24.82
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(3)	(3)
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Mwd		105.36
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Mwd	95.16	95.16
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	4	3
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Mwd	100.80	77.96
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per Mwd	29.30	4.68
Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(12)	(12)
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(4)
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(12)
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	48.34	48.69
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	25.79	25.83
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(27)
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu		4.45
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu		4.07
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(11)
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh		48.69
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh		25.83
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(27)
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu		4.45
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu		4.07
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)		(11)
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh		48.69
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh		25.83
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(9)	5
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	4.55	4.51
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair Value Inputs Price Per MMBtu	3.47	3.30
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	1	1
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	0.46	39.22
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	(0.09)	27.17
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	13	(1)
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	54.19	57.50
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price per MWh	26.20	25.90
Duke Energy Ohio [Member] | Derivative Financial Instruments Liabilities Reserves [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	(11)	(11)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Net derivative asset (liability)	$ 14	$ 10
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	10.86	35.43
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Net Derivative Asset (Liability) Fair Value Inputs [Line Items]
Fair value inputs, price FTR	(1.53)	23.63