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	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 374	$ 264
Location and fair value amounts of derivatives (Liability)	720	917
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	159	127
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	175	96
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	338	402
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	265	295
Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	21	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)	21	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)	52	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)	14	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
Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	353	255
Location and fair value amounts of derivatives (Liability)	653	798
Nondesignated [Member] | Interest Rate Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	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)	4	8
Nondesignated [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	46	41
Location and fair value amounts of derivatives (Liability)	1	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)	167	106
Location and fair value amounts of derivatives (Liability)	104	50
Nondesignated [Member] | Commodity Contracts [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	136	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)	4	2
Location and fair value amounts of derivatives (Liability)	171	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)	3	11
Location and fair value amounts of derivatives (Liability)	285	440
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	3
Progress Energy [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] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	159	244
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	122	192
Progress Energy [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	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)		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)	3	11
Location and fair value amounts of derivatives (Liability)	284	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)	1
Location and fair value amounts of derivatives (Liability)	159	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)	125	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)	108	166
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		1
Duke Energy Progress [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] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	65	97
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	43	69
Duke Energy Progress [Member] | Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)		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
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
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)	108	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 (Liability)	65	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 (Asset)	1
Location and fair value amounts of derivatives (Liability)	43	68
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2	9
Location and fair value amounts of derivatives (Liability)	173	270
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	2
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1	7
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	94	147
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	79	123
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)	2	9
Location and fair value amounts of derivatives (Liability)	173	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)	1
Location and fair value amounts of derivatives (Liability)	94	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)	1
Location and fair value amounts of derivatives (Liability)	79	123
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	314	220
Location and fair value amounts of derivatives (Liability)	290	199
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	155	137
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	159	81
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	165	136
Duke Energy Ohio [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	120	55
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)	314	218
Location and fair value amounts of derivatives (Liability)	290	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
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)	4	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)	21	31
Location and fair value amounts of derivatives (Liability)	6	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)	158	81
Location and fair value amounts of derivatives (Liability)	103	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)	134	106
Location and fair value amounts of derivatives (Liability)	160	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)	17	4
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14	10
Location and fair value amounts of derivatives (Liability)		63
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14
Duke Energy Indiana [Member] | Nondesignated [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	14	10
Location and fair value amounts of derivatives (Liability)		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)		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)	$ 14	$ 10