Business Segments (Business Segment Data) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 6,709		$ 6,722		$ 18,486		$ 13,929
Segment income	990	[1],[2],[3],[4]	590	[5],[6]	1,966	[1],[2],[3],[7],[8],[9]	1,328	[10],[11]
Add back Noncontrolling interest component	4		4		7		12
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	14		4		11		5
Net Income (Loss)	1,008		598		1,984		1,345
Segment Reporting Information Assets [Abstract]
Segment assets	114,590				114,590				113,856
Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,709	[1],[2],[3]	6,722		18,486	[1],[2],[3]	13,929
Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	0		0		0		0
U S Franchised Electric And Gas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,786		5,842		15,766		11,207
Segment income	923	[1],[2],[3]	790	[5]	1,932	[1],[2],[3],[7],[8]	1,263	[10]
Segments Notes To Tables [Abstract]
After-tax deferral of voluntary severance program expense							60
Segment Reporting Information Assets [Abstract]
Segment assets	99,269				99,269
U S Franchised Electric And Gas [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,768	[1],[2],[3]	5,830		15,731	[1],[2],[3]	11,178
U S Franchised Electric And Gas [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	18		12		35		29
Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	550		525		1,559		1,607
Segment income	27		12		26		71
Segment Reporting Information Assets [Abstract]
Segment assets	6,852				6,852
Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	541		508		1,527		1,560
Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	9		17		32		47
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	370		382		1,168		1,181
Segment income	116		103		300		350
Segment Reporting Information Assets [Abstract]
Segment assets	5,669				5,669
International Energy [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	370		382		1,168		1,181
International Energy [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues			0		0		0
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,706		6,749		18,493		13,995
Segment income	1,066	[1],[2],[3]	905	[5]	2,258	[1],[2],[3],[7],[8]	1,684	[10]
Segment Reporting Information Assets [Abstract]
Segment assets	111,790				111,790
Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,679	[1],[2],[3]	6,720		18,426	[1],[2],[3]	13,919
Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	27		29		67		76
All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	54		20		125		51
Segment income	(76)	[4]	(315)	[6]	(292)	[9]	(356)	[11]
Segments Notes To Tables [Abstract]
After-tax costs to achieve the merger	54		293		139		306
Segment Reporting Information Assets [Abstract]
Segment assets	2,658				2,658
All Other Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	30		2		60		10
All Other Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	24		18		65		41
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(51)		(47)		(132)		(117)
Segment Reporting Information Assets [Abstract]
Segment assets	142				142
Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(51)		(47)		(132)		(117)
Duke Energy Carolinas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	1,919		1,939		5,239		5,056
Net Income (Loss)	342		258		767		735
Segment Reporting Information Assets [Abstract]
Segment assets	31,552				31,552				30,642
Duke Energy Carolinas [Member] | Rate Case Step One [Member] | NCUC [Member]
Segments Notes To Tables [Abstract]
Approved rate increase amount by state commission					205
Duke Energy Carolinas [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(26)		(119)		(69)		(137)
Progress Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	2,766		2,788		7,233		7,178
Add back Noncontrolling interest component	1		2		2		5
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	14		3		10		10
Net Income (Loss)	342		157		479		373
Segment Reporting Information Assets [Abstract]
Segment assets	37,430				37,430				37,405
Progress Energy [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(72)		(181)		(205)		(278)
Duke Energy Progress [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	1,430		1,398		3,781		3,578
Net Income (Loss)	175		96		362		180
Segment Reporting Information Assets [Abstract]
Segment assets	18,542				18,542				18,068
Duke Energy Progress [Member] | Rate Case Step One [Member] | NCUC [Member]
Segments Notes To Tables [Abstract]
Approved rate increase amount by state commission					147
Duke Energy Progress [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(20)		(109)		(40)		(119)
Duke Energy Florida [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	1,332		1,388		3,442		3,594
Net Income (Loss)	197		100		250		311
Segment Reporting Information Assets [Abstract]
Segment assets	14,845				14,845				15,180
Duke Energy Florida [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(6)		(23)		(18)		(30)
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	819		757		2,377		2,386
Segment income	59	[12]	14		96	[12]	133
Net Income (Loss)	59		14		96		133
Segment Reporting Information Assets [Abstract]
Segment assets	10,657				10,657				10,560
Duke Energy Ohio [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	819	[12]	757		2,377	[12]	2,386
Duke Energy Ohio [Member] | Electric Rate Case [Member] | PUCO [Member]
Segments Notes To Tables [Abstract]
Approved rate increase amount by state commission					49
Duke Energy Ohio [Member] | Franchised Electric & Gas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	421		431		1,317		1,291
Segment income	42	[12]	49		122	[12]	113
Segment Reporting Information Assets [Abstract]
Segment assets	6,631				6,631
Duke Energy Ohio [Member] | Franchised Electric & Gas [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	421	[12]	431		1,317	[12]	1,291
Duke Energy Ohio [Member] | DEO Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	404		341		1,085		1,137
Segment income	30		(17)		(3)		44
Segment Reporting Information Assets [Abstract]
Segment assets	4,088				4,088
Duke Energy Ohio [Member] | DEO Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	398		326		1,060		1,095
Duke Energy Ohio [Member] | DEO Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6		15		25		42
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	825		772		2,402		2,428
Segment income	72	[12]	32		119	[12]	157
Segment Reporting Information Assets [Abstract]
Segment assets	10,719				10,719
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	819	[12]	757		2,377	[12]	2,386
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6		15		25		42
Duke Energy Ohio [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(13)		(18)		(23)		(24)
Segment Reporting Information Assets [Abstract]
Segment assets	103				103
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(6)		(15)		(25)		(42)
Segment Reporting Information Assets [Abstract]
Segment assets	(165)				(165)
Duke Energy Ohio [Member] | Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(6)		(15)		(25)		(42)
Duke Energy Indiana [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	755		718		2,179		2,091
Net Income (Loss)	104		(19)		276		(109)
Segment Reporting Information Assets [Abstract]
Segment assets	10,336				10,336				10,008
Duke Energy Indiana [Member] | All Other Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	$ (5)		$ (14)		$ (13)		$ (19)

[1] In May 2013, Duke Energy Ohio implemented revised customer rates approved by the PUCO. This increase impacts USFE&G. See Note 4 for additional information about the revised customer rates.

[2] In June 2013, Duke Energy Progress implemented revised customer rates approved by the NCUC. This increase impacts USFE&G. See Note 4 for additional information about the revised customer rates.

[3] In September 2013, Duke Energy Carolinas implemented revised customer rates approved by the NCUC and the PSCSC. This increase impacts USFE&G. See Note 4 for additional information about the revised customer rates.

[4] Other includes after-tax costs to achieve the merger with Progress Energy of $54 million. See Note 2 for additional information about the merger.

[5] USFE&G recorded an impairment related to the Edwardsport Integrated Gasification Combined Cycle (IGCC) project. See Note 4 for additional information on the Edwardsport impairment.

[6] Other includes after-tax costs to achieve the merger with Progress Energy of $293 million. See Note 2 for additional information about the merger.

[7] USFE&G recorded an impairment charge related to Duke Energy Florida's Crystal River Unit 3. See Note 4 for additional information about the Crystal River Unit 3 impairment.

[8] USFE&G recorded an impairment charge related to Duke Energy Progress' Shearon Harris Nuclear Station (Harris) site. USFE&G also recorded an impairment charge related to Duke Energy Florida's proposed Levy Nuclear Station (Levy). See Note 4 for additional information about the Harris site and Levy site impairments.

[9] Other includes after-tax costs to achieve the merger with Progress Energy of $139 million. See Note 2 for additional information about the merger.

[10] USFE&G recorded an impairment charge related to Duke Energy Indiana's IGCC project. USFE&G also recorded the reversal of expenses of $60 million related to a prior year Voluntary Opportunity Plan in accordance with Duke Energy Carolinas' 2011 rate case. See Note 4 for additional information about the impairment charges.

[11] Other includes after-tax costs to achieve the merger with Progress Energy of $306 million. See Note 2 for additional information about the merger.

[12] In May 2013, Duke Energy Ohio implemented revised customer rates approved by the PUCO. This increase impacts FE&G. See Note 4 for additional information about the revised customer rates.