Risk Management, Derivative Instruments And Hedging Activities (Location And Fair Value Amounts Of Derivatives Reflected In The Condensed Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 309		$ 264
Location and fair value amounts of derivatives (Liability)	845		917
Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3		9
Location and fair value amounts of derivatives (Liability)	102		119
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2		2
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3		7
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	(2)
Location and fair value amounts of derivatives (Liability)	70		81
Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	30		35
Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		2
Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		1
Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	306		255
Location and fair value amounts of derivatives (Liability)	743		798
Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	57		76
Nondesignated [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6		8
Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	52		41
Location and fair value amounts of derivatives (Liability)	9		2
Nondesignated [Member] | Commodity Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	32		106
Location and fair value amounts of derivatives (Liability)	6		50
Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	151		106
Location and fair value amounts of derivatives (Liability)	372		407
Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	71		2
Location and fair value amounts of derivatives (Liability)	293		255
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5		12
Duke Energy Carolinas [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	5		12
Duke Energy Carolinas [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2		6
Duke Energy Carolinas [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	3		6
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	47		11
Location and fair value amounts of derivatives (Liability)	301		440
Progress Energy [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)			3
Progress Energy [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2
Progress Energy [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		2
Progress Energy [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		1
Progress Energy [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	47		11
Location and fair value amounts of derivatives (Liability)	299		437
Progress Energy [Member] | Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)			11
Progress Energy [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13		3
Progress Energy [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2		8
Progress Energy [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	20
Location and fair value amounts of derivatives (Liability)	140		231
Progress Energy [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12
Location and fair value amounts of derivatives (Liability)	159		195
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14		2
Location and fair value amounts of derivatives (Liability)	108		166
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2		2
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		1
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		1
Duke Energy Progress [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14		2
Location and fair value amounts of derivatives (Liability)	106		164
Duke Energy Progress [Member] | Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)			11
Duke Energy Progress [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	[1]	1	[1]
Duke Energy Progress [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)			1	[1]
Duke Energy Progress [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	[1]
Location and fair value amounts of derivatives (Liability)	52	[1]	85	[1]
Duke Energy Progress [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	[1]
Location and fair value amounts of derivatives (Liability)	54	[1]	68	[1]
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	33		9
Location and fair value amounts of derivatives (Liability)	190		270
Duke Energy Florida [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)			1
Duke Energy Florida [Member] | Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)			1
Duke Energy Florida [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	33		9
Location and fair value amounts of derivatives (Liability)	190		269
Duke Energy Florida [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	[1]	2	[1]
Duke Energy Florida [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	[1]	7	[1]
Duke Energy Florida [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	[1]
Location and fair value amounts of derivatives (Liability)	89	[1]	146	[1]
Duke Energy Florida [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10	[1]
Location and fair value amounts of derivatives (Liability)	101	[1]	123	[1]
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	244		220
Location and fair value amounts of derivatives (Liability)	319		199
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2		2
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2		2
Duke Energy Ohio [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	242		218
Location and fair value amounts of derivatives (Liability)	319		199
Duke Energy Ohio [Member] | Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1		1
Duke Energy Ohio [Member] | Nondesignated [Member] | Interest Rate Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6		7
Duke Energy Ohio [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	42		31
Location and fair value amounts of derivatives (Liability)	32		4
Duke Energy Ohio [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Investments And Other Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13		81
Location and fair value amounts of derivatives (Liability)	7		51
Duke Energy Ohio [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	130		106
Location and fair value amounts of derivatives (Liability)	182		132
Duke Energy Ohio [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Deferred Credits And Other Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	57
Location and fair value amounts of derivatives (Liability)	91		4
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5		10
Location and fair value amounts of derivatives (Liability)	55		63
Duke Energy Indiana [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5		10
Location and fair value amounts of derivatives (Liability)	55		63
Duke Energy Indiana [Member] | Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	55		63
Duke Energy Indiana [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 5		$ 10

[1] Substantially all of these contracts receive regulatory treatment.