Business Segments (Business Segment Data) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 6,624		$ 5,898
Interest Expense	406		367
Segment income	(94)	[1],[2]	634	[3]
Add back Noncontrolling interest component	4		0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(3)		0
Net Income (Loss)	(93)		634
Segment Reporting Information Assets [Abstract]
Segment assets	113,792				114,779
Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,624		5,898
Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	0		0
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,805		5,060
Segment income	737		656
Segment Reporting Information Assets [Abstract]
Segment assets	100,097
Regulated Utilities [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,795		5,052
Regulated Utilities [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	10		8
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	382		392
Segment income	130		97
Segment Reporting Information Assets [Abstract]
Segment assets	5,064
International Energy [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	382		392
International Energy [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues			0
Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	449		452
Segment income	(879)	[1]	(42)
Segment Reporting Information Assets [Abstract]
Segment assets	5,666	[1]
Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	442		439
Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	7		13
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,636		5,904
Segment income	(12)	[1]	711
Segment Reporting Information Assets [Abstract]
Segment assets	110,827	[1]
Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	6,619		5,883
Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	17		21
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	25		35
Segment income	(82)	[2]	(77)	[3]
Segment Reporting Information Assets [Abstract]
Segment assets	2,789
Other [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5		15
Other [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	20		20
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(37)		(41)
Segment Reporting Information Assets [Abstract]
Segment assets	176
Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(37)		(41)
Duke Energy Carolinas [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	2,000		1,729
Interest Expense	101		82
Net Income (Loss)	286		244
Segment Reporting Information Assets [Abstract]
Segment assets	31,319				31,273
Duke Energy Carolinas [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(21)		(19)
Progress Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	2,541		2,186
Interest Expense	169		198
Add back Noncontrolling interest component	1		1
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(1)
Net Income (Loss)	203		154
Segment Reporting Information Assets [Abstract]
Segment assets	37,984				37,969
Progress Energy [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest Expense	63		101
Segment income	(52)		(79)
Duke Energy Progress [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	1,422		1,216
Interest Expense	57		48
Net Income (Loss)	133		110
Segment Reporting Information Assets [Abstract]
Segment assets	19,308				18,909
Duke Energy Progress [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(10)		(7)
Duke Energy Florida [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	1,116		968
Interest Expense	49		49
Net Income (Loss)	108		110
Segment Reporting Information Assets [Abstract]
Segment assets	14,733				14,757
Duke Energy Florida [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(4)		(5)
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	763		747
Interest Expense	22		18
Segment income	(890)	[1],[4]	(21)
Net Income (Loss)	(890)		(21)
Segment Reporting Information Assets [Abstract]
Segment assets	9,535				10,763
Duke Energy Ohio [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	763	[4]	747
Duke Energy Ohio [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	562		492
Segment income	64	[4]	53
Segment Reporting Information Assets [Abstract]
Segment assets	6,736
Duke Energy Ohio [Member] | Regulated Utilities [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	562	[4]	492
Duke Energy Ohio [Member] | Commercial Power [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	208		266
Segment income	(951)	[1]	(67)
Segment Reporting Information Assets [Abstract]
Segment assets	2,858	[1]
Duke Energy Ohio [Member] | Commercial Power [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	201		255
Duke Energy Ohio [Member] | Commercial Power [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	7		11
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	770		758
Segment income	(887)	[1],[4]	(14)
Segment Reporting Information Assets [Abstract]
Segment assets	9,594	[1]
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Unaffiliated [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	763	[4]	747
Duke Energy Ohio [Member] | Total Reportable Segments [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	7		11
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	(3)		(7)
Segment Reporting Information Assets [Abstract]
Segment assets	102
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(7)		(11)
Segment Reporting Information Assets [Abstract]
Segment assets	(161)
Duke Energy Ohio [Member] | Intersegment Eliminations [Member] | Intersegment [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(7)		(11)
Duke Energy Indiana [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	845		724
Interest Expense	43		41
Net Income (Loss)	113		90
Segment Reporting Information Assets [Abstract]
Segment assets	10,630				10,548
Duke Energy Indiana [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment income	$ (3)		$ (4)

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

[2] Other includes after-tax costs to achieve the Progress Energy merger.

[3] Other includes after-tax costs to achieve the Progress Energy merger.

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