Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating revenues	$ 5,729	$ 5,377
Segment income	716	574
Add back noncontrolling interests	1	3
Income From Discontinued Operations, net of tax		122
Net Income	717	699
Net Income Attributable to Parent	716	694
Segment assets	134,108		$ 132,761
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	4,939	5,081
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	648	169
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	128	114
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	14	13
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,715	5,364
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	4,947	5,089
Segment income	635	664
Segment assets	115,766
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	670	170
Segment income	133	32
Segment assets	10,866
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	128	114
Segment income	25	26
Segment assets	4,400
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,745	5,373
Segment income	793	722
Segment assets	131,032
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(25)
Segment assets	178
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	(8)	(8)
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	(22)	(1)
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	(19)	(16)
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	(30)	(9)
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	33	29
Segment income	(77)	(148)
Segment assets	2,898
Costs to achieve mergers		74
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	518	516
Segment income	42	57
Income From Discontinued Operations, net of tax		2
Net Income Attributable to Parent	42	59
Segment assets	7,609		$ 7,528
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	337	340
Segment income	24	36
Segment assets	4,856
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	170	170
Segment income	26	31
Segment assets	2,696
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	507	510
Segment income	50	67
Segment assets	7,552
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment income		(1)
Segment assets	(14)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	11	6
Segment income	(8)	$ (9)
Segment assets	$ 71