Fair Value Of Financial Assets and Liabilities (Quantitative Level 3 Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	$ (82)	$ (53)
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	10.36	9.99
Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	2.91	2.33
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(8)	(23)
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	49.29	48.69
FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	23.15	25.83
Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	19	11
Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	10.83	39.22
Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	(3.25)	23.63
Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	3	(8)
Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	55.52	77.96
Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.30	24.82
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(3)	(3)
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	4.88	105.36
Commodity Capacity Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	2.91	95.16
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	2	3
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	85.70	77.96
Commodity Capacity Option Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per Mwd	29.80	4.68
Derivative Financial Instruments Liabilities Reserves [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(18)	(12)
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(4)	(12)
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	49.29	48.69
Duke Energy Carolinas [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.92	25.83
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(31)	(27)
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.39	4.45
Progress Energy [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.00	4.07
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(4)	(11)
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	43.56	48.69
Progress Energy [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	23.15	25.83
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(31)	(27)
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.39	4.45
Duke Energy Progress [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.00	4.07
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(4)	(11)
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	43.56	48.69
Duke Energy Progress [Member] | FERC Mitigation Power Sale Agreements [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	23.15	25.83
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(14)	5
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	4.88	4.51
Duke Energy Ohio [Member] | Commodity Natural Gas Hedges [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs Price Per MMBtu	2.91	3.30
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	1	1
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	0.94	39.22
Duke Energy Ohio [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	(0.20)	27.17
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	11	(1)
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	55.52	57.50
Duke Energy Ohio [Member] | Commodity Power Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price per MWh	25.30	25.90
Duke Energy Ohio [Member] | Derivative Financial Instruments Liabilities Reserves [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	(17)	(11)
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative financial instruments liabilities fair value disclosure	$ 18	$ 10
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	10.83	35.43
Duke Energy Indiana [Member] | Financial Transmission Rights [Member] | RTO Market Pricing [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value inputs, price FTR	(3.25)	23.63