Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating revenues	$ 6,163	$ 6,135
Segment income (loss)	900	620
Add back noncontrolling interest component	(7)	2
Net Income	893	622
Net income (attributable to parent)	900	620
Segment assets	151,136		$ 145,392
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,321	5,315
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	732	702
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	106	101
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,159	6,118
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	4	17
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	989	886
Segment assets	147,423
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	5,329	5,323
Segment income (loss)	750	750
Segment assets	130,406
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	756	727
Segment income (loss)	226	116
Segment assets	12,639
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	106	101
Segment income (loss)	13	20
Segment assets	4,378
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,191	6,151
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(51)
Segment assets	177
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	24	25
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	32	33
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	17	18
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	(89)	(266)
Segment assets	3,536
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	21	35
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	531	524
Segment income (loss)	69	(25)
Net income (attributable to parent)	69	(25)
Segment assets	9,144		$ 8,555
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	355	336
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	176	174
Duke Energy Ohio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	531	510
Segment income (loss)	71	67
Segment assets	9,109
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	36	33
Segment assets	6,058
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income (loss)	35	34
Segment assets	3,051
Duke Energy Ohio [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment assets	(2)
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating revenues		14
Segment income (loss)	(2)	$ (92)
Segment assets	$ 37