Business Segments (Business Segment Data) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 5,949		$ 5,879		$ 12,573		$ 11,777
Segment income	612		342		518		976
Add back noncontrolling interests component	4		3		8		3
Loss from discontinued operations, net of tax	(3)		(3)		(6)		(3)
Net income (loss)	613		342		520		976
Segment assets	115,173				115,173				114,779
Income tax benefit	209		165		82		495
Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,949		5,879		12,573		11,777
Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,283		4,920		11,088		9,980
Segment income	689		353	[1],[2],[3],[4]	1,426		1,009	[1],[3],[4],[5]
Segment assets	101,070				101,070
Regulated Utilities [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,272		4,911	[1],[2]	11,067		9,963	[1],[5]
Regulated Utilities [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	11		9		21		17
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	364		406		746		798
Segment income	146		87		276		184
Segment assets	5,463				5,463
International Energy [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	364		406		746		798
International Energy [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues
Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	309		557		758		1,009
Segment income	(120)	[6]	41		(999)	[7],[8]	(1)
Segment assets	5,652				5,652
Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	304		547		746		986
Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5		10		12		23
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,956		5,883		12,592		11,787
Segment income	715		481		703		1,192
Segment assets	112,185				112,185
Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,940		5,864		12,559		11,747
Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	16		19		33		40
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	28		36		53		71
Segment income	(103)	[9]	(139)	[9]	(185)	[9]	(216)	[9]
Segment assets	2,807				2,807
Other [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	9		15		14		30
Other [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	19		21		39		41
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(35)		(40)		(72)		(81)
Segment assets	181				181
Intersegment Eliminations [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues
Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(35)		(40)		(72)		(81)
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	531		811		1,294		1,558
Segment income	(107)		58		(997)		37
Segment assets	9,569				9,569				10,763
Income tax benefit	(62)		33		(549)		21
Duke Energy Ohio [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	531		811		1,294		1,558
Duke Energy Ohio [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	415		404		977		896
Segment income	52	[10]	27	[10]	116	[10]	80	[10]
Segment assets	7,203				7,203
Duke Energy Ohio [Member] | Regulated Utilities [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	415	[10]	404	[10]	977	[10]	896	[10]
Duke Energy Ohio [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	121		415		329		681
Segment income	(154)	[11]	35		(1,105)	[12],[7]	(33)
Segment assets	2,818				2,818
Duke Energy Ohio [Member] | Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	116		407		317		662
Duke Energy Ohio [Member] | Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5		8		12		19
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	536		819		1,306		1,577
Segment income	(102)		62		(989)		47
Segment assets	10,021				10,021
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	531		811		1,294		1,558
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5		8		12		19
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues
Segment income	(5)		(4)		(8)		(10)
Segment assets	103				103
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(5)		(8)		(12)		(19)
Segment assets	(555)				(555)
Duke Energy Ohio [Member] | Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(5)		(8)		(12)		(19)
Commodity Contracts [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Unrealized gain (loss) on commodity contracts	(136)				(158)
Income tax benefit	(77)				(89)
Commodity Contracts [Member] | Duke Energy Ohio [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Unrealized gain (loss) on commodity contracts	(148)				(181)
Income tax benefit	$ (84)				$ (101)

[1] In May 2013, the PUCO approved a Duke Energy Ohio settlement agreement that provides for a net annual increase in electric distribution revenues beginning in May 2013. This rate increase impacts Regulated Utilities.

[2] In May 2013, the NCUC approved a Duke Energy Progress settlement agreement that included an increase in rates beginning in June 2013. This rate increase impacts Regulated Utilities.

[3] Regulated Utilities recorded an impairment charge related to the letter Duke Energy Progress filed with the NRC requesting the NRC to suspend its review activities associated with the combined construction and operating license (COL) at the Shearon Harris Nuclear Station (Harris) site. Regulated Utilities also recorded an impairment charge related to the write-off of the wholesale portion of the Levy investments at Duke Energy Florida in accordance with the 2013 Settlement. See Note 4 for additional information.

[4] Regulated Utilities recorded an impairment charge related to Duke Energy Florida's Crystal River Unit 3. See Note 4 for additional information.

[5] In May 2013, the NCUC approved a Duke Energy Progress settlement agreement that included an increase in rates in the first year beginning in June 2013. This rate increase impacts Regulated Utilities.

[6] Commercial Power includes a mark-to-market loss of $136 million, net of a tax benefit of $77 million, on economic hedges of the input and output commodities related to its fossil generation assets.

[7] Commercial Power includes an impairment charge related to the planned disposition of the Midwest Generation assets. See Note 2 for additional information.

[8] Commercial Power includes a mark-to-market loss of $158 million, net of a tax benefit of $89 million, on economic hedges of the input and output commodities related to its fossil generation assets.

[9] Other includes costs to achieve the Progress Energy merger.

[10] In May 2013, the PUCO approved a settlement agreement that provides for a net annual increase in electric distribution revenues beginning in May 2013. This increase impacts Regulated Utilities.

[11] Commercial Power includes an after-tax mark-to-market loss of $148 million, net of a tax benefit of $84 million, on economic hedges of the input and output commodities related to its fossil generation assets.

[12] Commercial Power includes an after-tax mark-to-market loss of $181 million, net of a tax benefit of $101 million, on economic hedges of the input and output commodities related to its fossil generation assets.