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	Jun. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 369	$ 264
Location and fair value amounts of derivatives (Liability)	816	917
Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	9
Location and fair value amounts of derivatives (Liability)	67	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
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)	10	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 (Liability)	50	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 (Asset)	12
Location and fair value amounts of derivatives (Liability)	13	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)	3	1
Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	347	255
Location and fair value amounts of derivatives (Liability)	749	798
Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	37	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)	5	8
Nondesignated [Member] | Commodity Contracts [Member] | Current Assets Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	50	41
Location and fair value amounts of derivatives (Liability)	2	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)	137	106
Location and fair value amounts of derivatives (Liability)	93	50
Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	156	106
Location and fair value amounts of derivatives (Liability)	404	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)	4	2
Location and fair value amounts of derivatives (Liability)	208	255
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	12
Duke Energy Carolinas [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	4	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)	3	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)	1	6
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6	11
Location and fair value amounts of derivatives (Liability)	331	440
Progress Energy [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	2	3
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)	6	11
Location and fair value amounts of derivatives (Liability)	329	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)		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)		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)	4
Location and fair value amounts of derivatives (Liability)	175	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)	2
Location and fair value amounts of derivatives (Liability)	154	195
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Location and fair value amounts of derivatives (Liability)	125	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)	1	2
Location and fair value amounts of derivatives (Liability)	123	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)		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
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)	1
Location and fair value amounts of derivatives (Liability)	67	85
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 (Liability)	56	68
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	9
Location and fair value amounts of derivatives (Liability)	202	270
Duke Energy Florida [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	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	1
Duke Energy Florida [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	9
Location and fair value amounts of derivatives (Liability)	201	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)		2
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)		7
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)	3
Location and fair value amounts of derivatives (Liability)	107	146
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)	2
Location and fair value amounts of derivatives (Liability)	94	123
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	309	220
Location and fair value amounts of derivatives (Liability)	300	199
Duke Energy Ohio [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		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
Duke Energy Ohio [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	309	218
Location and fair value amounts of derivatives (Liability)	300	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)	5	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)	27	31
Location and fair value amounts of derivatives (Liability)	8	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)	129	81
Location and fair value amounts of derivatives (Liability)	93	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)	152	106
Location and fair value amounts of derivatives (Liability)	173	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)	1
Location and fair value amounts of derivatives (Liability)	20	4
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	18	10
Location and fair value amounts of derivatives (Liability)	37	63
Duke Energy Indiana [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	18	10
Location and fair value amounts of derivatives (Liability)	37	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)	35	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)	18	10
Duke Energy Indiana [Member] | Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 2