Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating revenues	$ 6,821	$ 6,483	$ 17,927	$ 18,137
Segment income	1,054	937	2,255	2,310
Add back noncontrolling interests	5	3	13	10
(Loss) Income From Discontinued Operations, net of tax	122	(5)	124	29
Net income (loss)	1,181	935	2,392	2,349
Segment assets	129,686		129,686		$ 121,156
Income Tax Benefit	520	420	972	1,118
Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,421	6,138	16,761	17,062
Impairment Charges, net of tax		56		56
International Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	245	281	761	841
Impairment Charges, net of tax			145
Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues	140	66	366	214
Impairment Charges, net of tax	45		45
State Tax Charge				41
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,806	6,485	17,888	18,117
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	15	(2)	39	20
Operating Segments [Member] | Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,430	6,147	16,788	17,090
Segment income	1,200	905	2,613	2,311
Segment assets	114,707		114,707
Operating Segments [Member] | International Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	245	281	761	841
Segment income	64	69	85	157
Segment assets	3,153		3,153
Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues	140	66	366	214
Segment income	(21)	8	20	(15)
Segment assets	4,414		4,414
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,815	6,494	17,915	18,145
Segment income	1,243	982	2,718	2,453
Segment assets	122,274		122,274
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(26)	(28)	(79)	(86)
Segment income				(4)
Segment assets	184		184
Intersegment Eliminations [Member] | Regulated Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	(9)	(9)	(27)	(28)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	(9)	(9)	(27)	(28)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	(17)	(19)	(52)	(58)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	32	17	91	78
Segment income	(189)	(45)	(463)	(139)
Segment assets	7,228		7,228
Costs to achieve merger	52	15	195	42
Cost Savings Initiative, Net of tax	12		39
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	489	462	1,433	1,453
(Loss) Income From Discontinued Operations, net of tax	34	(2)	36	23
Segment assets	7,408		7,408		$ 7,097
Income Tax Benefit	32	22	65	64
Charge for settlement agreement				53
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (10)	$ (12)	(29)	(20)
Duke Energy Ohio [Member] | Operating Segments [Member] | Commercial Portfolio [Member]
Segment Reporting Information [Line Items]
Operating revenues				14
Segment income				$ (9)
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Income Tax Benefit			$ 122