Derivatives and Hedging (Location and Fair Value Amounts of Derivatives Reflected in the Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 33	$ 351
Location and fair value amounts of derivatives (Liability)	406	909
Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	26	210
Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	136
Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	257	573
Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	144	319
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	22	339
Location and fair value amounts of derivatives (Liability)	342	859
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	12
Location and fair value amounts of derivatives (Liability)	64	50
Designated As Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	1
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)	1	10
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)	14	13
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)	41	29
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	17	18
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		15
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		3
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		15
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current 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)	242	307
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		174
Location and fair value amounts of derivatives (Liability)		253
Not 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 (Asset)	2	2
Location and fair value amounts of derivatives (Liability)	100	91
Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		111
Location and fair value amounts of derivatives (Liability)		208
Not 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)	6	2
Not 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)	4
Not 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)	1	1
Not 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)	8	7
Duke Energy Carolinas [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	19
Duke Energy Carolinas [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	25	14
Duke Energy Carolinas [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	8	5
Duke Energy Carolinas [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	33	19
Duke Energy Carolinas [Member] | Not 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)	25	14
Duke Energy Carolinas [Member] | Not 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)	8	5
Progress Energy [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	13	2
Location and fair value amounts of derivatives (Liability)	309	371
Progress Energy [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	7	2
Progress Energy [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Progress Energy [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	215	289
Progress Energy [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	89	82
Progress Energy [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	306	369
Progress Energy [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	10	2
Location and fair value amounts of derivatives (Liability)	3	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
Progress Energy [Member] | Not Designated as Hedging Instrument [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)	215	288
Progress Energy [Member] | Not 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 (Asset)	2
Location and fair value amounts of derivatives (Liability)	91	80
Progress Energy [Member] | Not 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)	6	2
Progress Energy [Member] | Not 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)	4
Progress Energy [Member] | Not 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)	3	2
Duke Energy Progress [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Location and fair value amounts of derivatives (Liability)	95	132
Duke Energy Progress [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
Duke Energy Progress [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	77	109
Duke Energy Progress [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	18	23
Duke Energy Progress [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	93	132
Duke Energy Progress [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	2
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] | Not 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)	77	108
Duke Energy Progress [Member] | Not 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)	16	23
Duke Energy Progress [Member] | Not 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 Progress [Member] | Not 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)	2
Duke Energy Florida [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	11	2
Location and fair value amounts of derivatives (Liability)	209	239
Duke Energy Florida [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	5	2
Duke Energy Florida [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	6
Duke Energy Florida [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	138	180
Duke Energy Florida [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	71	59
Duke Energy Florida [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	3
Location and fair value amounts of derivatives (Liability)	209	237
Duke Energy Florida [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	8	2
Location and fair value amounts of derivatives (Liability)		2
Duke Energy Florida [Member] | Not Designated as Hedging Instrument [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)	138	180
Duke Energy Florida [Member] | Not 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 (Asset)	2
Location and fair value amounts of derivatives (Liability)	71	57
Duke Energy Florida [Member] | Not 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)	4	2
Duke Energy Florida [Member] | Not 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)	4
Duke Energy Florida [Member] | Not 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)		2
Duke Energy Ohio [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	341
Location and fair value amounts of derivatives (Liability)	7	473
Duke Energy Ohio [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	204
Duke Energy Ohio [Member] | Investments And Other Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		137
Duke Energy Ohio [Member] | Current Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	1	257
Duke Energy Ohio [Member] | Deferred Credits And Other Liabilities, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	6	216
Duke Energy Ohio [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	4	341
Location and fair value amounts of derivatives (Liability)		467
Duke Energy Ohio [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Liability)	$ 7	6
Duke Energy Ohio [Member] | 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)
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 4	1
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		28
Location and fair value amounts of derivatives (Liability)		4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Investments And Other Assets, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		26
Location and fair value amounts of derivatives (Liability)		4
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Liabilities, Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		175
Location and fair value amounts of derivatives (Liability)		252
Duke Energy Ohio [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Deferred Credits and Other Liabilities Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)		111
Location and fair value amounts of derivatives (Liability)		207
Duke Energy Ohio [Member] | Not 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)	1	1
Duke Energy Ohio [Member] | Not 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)	6	5
Duke Energy Indiana [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	12	14
Duke Energy Indiana [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contracts [Member] | Current Assets, Other [Member]
Derivatives, Fair Value [Line Items]
Location and fair value amounts of derivatives (Asset)	$ 12	$ 14