Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	$ 5,589	$ 5,708	$ 11,654	$ 11,971
Segment income	600	722	1,373	1,468
Add back noncontrolling interests component	4	4	7	8
(Loss) Income From Discontinued Operations, net of tax	(57)	(113)	34	(956)
Net income (loss) attributable to parent	543	609	1,407	512
Net income (loss)	547	613	1,414	520
Segment assets	118,575		118,575		$ 120,709
Impairment charges		(16)		80
Charge for agreement in principle, net of tax	46		53
Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,211	5,272	10,924	11,067
International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	287	364	560	746
Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	75	64	148	145
State Tax Charge	41		41
Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	16	8	22	13
Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,573	5,700	11,632	11,958
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,220	5,283	10,943	11,088
Segment income	632	689	1,406	1,426
Segment assets	108,139		108,139
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	287	364	560	746
Segment income	52	146	88	276
Segment assets	3,913		3,913
Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	75	64	148	145
Segment income	(33)	(21)	(32)	(53)
Segment assets	3,462		3,462
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	5,582	5,711	11,651	11,979
Segment income	651	814	1,462	1,649
Segment assets	115,514		115,514
Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(27)	(32)	(58)	(62)
Segment income	(3)	(2)	(4)	(4)
Segment assets	181		181
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(11)	(19)	(21)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(18)	(21)	(39)	(41)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	(9)	(11)	(19)	(21)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	34	29	61	54
Segment income	(48)	(90)	(85)	(177)
Segment assets	2,880		2,880
Costs to achieve Progress Energy merger	14	38	27	72
Other VIEs [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				94
Duke Energy Ohio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	405	412	991	987
Segment income	13	28	72	13
(Loss) Income From Discontinued Operations, net of tax	(65)	(135)	25	(1,010)
Net income (loss) attributable to parent	(52)	(107)	97	(997)
Segment assets	7,022		7,022		9,999
Impairment charges				94
Charge for agreement in principle, net of tax	46		53
Duke Energy Ohio [Member] | Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	396	415	968	977
Segment income	19	47	89	108
Segment assets	6,941		6,941
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		(3)	14	10
Segment income		(14)	(9)	(88)
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues		412	982	987
Segment income		33	80	20
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Segment assets	(25)		(25)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Operating revenues	9		9
Segment income	(6)	$ (5)	(8)	(7)
Segment assets	$ 106		$ 106
Duke Energy Ohio [Member] | Other VIEs [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				94	$ 94
Duke Energy Ohio [Member] | Other VIEs [Member] | Commercial Portfolio [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Impairment charges				$ 94