Fair Value Of Financial Assets And Liabilities (Quantitative Level 3 Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	9.99
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Progress Energy [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.45
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Progress Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.45
Commodity Natural Gas Hedges [Member] | Maximum [Member] | Duke Energy Ohio [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.51
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	2.33
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Progress Energy [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.07
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Progress Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.07
Commodity Natural Gas Hedges [Member] | Minimum [Member] | Duke Energy Ohio [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	3.30
FERC Mitigation Power Sale Agreements [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	48.69
FERC Mitigation Power Sale Agreements [Member] | Maximum [Member] | Duke Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	48.69
FERC Mitigation Power Sale Agreements [Member] | Maximum [Member] | Progress Energy [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	48.69
FERC Mitigation Power Sale Agreements [Member] | Maximum [Member] | Progress Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	48.69
FERC Mitigation Power Sale Agreements [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.83
FERC Mitigation Power Sale Agreements [Member] | Minimum [Member] | Duke Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.83
FERC Mitigation Power Sale Agreements [Member] | Minimum [Member] | Progress Energy [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.83
FERC Mitigation Power Sale Agreements [Member] | Minimum [Member] | Progress Energy Carolinas [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.83
Financial Transmission Rights [Member] | Maximum [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	39.22
Financial Transmission Rights [Member] | Maximum [Member] | Duke Energy Ohio [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	39.22
Financial Transmission Rights [Member] | Maximum [Member] | Duke Energy Indiana [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	35.43
Financial Transmission Rights [Member] | Minimum [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	23.63
Financial Transmission Rights [Member] | Minimum [Member] | Duke Energy Ohio [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	27.17
Financial Transmission Rights [Member] | Minimum [Member] | Duke Energy Indiana [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	23.63
Commodity Power Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	77.96
Commodity Power Contracts [Member] | Maximum [Member] | Duke Energy Ohio [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	57.50
Commodity Power Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	24.82
Commodity Power Contracts [Member] | Minimum [Member] | Duke Energy Ohio [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.90
Commodity Capacity Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	105.36
Commodity Capacity Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	95.16
Commodity Capacity Option Contracts [Member] | Maximum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	77.96
Commodity Capacity Option Contracts [Member] | Minimum [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	4.68
Level 3 [Member] | Commodity Natural Gas Hedges [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	$ (53)
Level 3 [Member] | Commodity Natural Gas Hedges [Member] | Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(27)
Level 3 [Member] | Commodity Natural Gas Hedges [Member] | Progress Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(27)
Level 3 [Member] | Commodity Natural Gas Hedges [Member] | Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	5
Level 3 [Member] | FERC Mitigation Power Sale Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(23)
Level 3 [Member] | FERC Mitigation Power Sale Agreements [Member] | Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(12)
Level 3 [Member] | FERC Mitigation Power Sale Agreements [Member] | Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(11)
Level 3 [Member] | FERC Mitigation Power Sale Agreements [Member] | Progress Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(11)
Level 3 [Member] | Financial Transmission Rights [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	11
Level 3 [Member] | Financial Transmission Rights [Member] | Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	1
Level 3 [Member] | Financial Transmission Rights [Member] | Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	10
Level 3 [Member] | Commodity Power Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(8)
Level 3 [Member] | Commodity Power Contracts [Member] | Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(1)
Level 3 [Member] | Commodity Capacity Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(3)
Level 3 [Member] | Commodity Capacity Option Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	3
Level 3 [Member] | Derivative Financial Instruments Liabilities Reserves [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	(12)
Level 3 [Member] | Derivative Financial Instruments Liabilities Reserves [Member] | Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Financial Instruments Liabilities Fair Value Disclosure	$ (11)