Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Operating revenues	$ 6,482	$ 6,576	$ 17,766	$ 17,166
Segment income	956	999	2,360	2,197
Add back noncontrolling interests	1	2	5	5
(Loss) Income From Discontinued Operations, net of tax	(2)	180	(4)	190
Net income	955	1,181	2,361	2,392
Net income	954	1,176	2,356	2,379
Segment assets	136,325		136,325		$ 132,761
Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,129	6,340	16,234	16,430
Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	272	89	1,243	358
Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	95	139	333	365
Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	35	32	103	91
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,496	6,568	17,810	17,153
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,122	6,332	16,211	16,406
Segment income	1,020	1,189	2,384	2,557
Segment assets	118,323		118,323
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	249	89	1,175	355
Segment income	19	15	179	63
Segment assets	11,361		11,361
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Operating revenues	95	139	333	365
Segment income	(49)	(24)	2	13
Segment assets	4,216		4,216
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	6,466	6,560	17,719	17,126
Segment income	990	1,180	2,565	2,633
Segment assets	133,900		133,900
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(24)	(147)	(78)
Segment assets	185		185
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	7	8	23	24
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	23		68	3
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	19	16	56	51
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	30	8	91	27
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	16	16	47	40
Segment income	(34)	(181)	(205)	(436)
Segment assets	2,240		2,240
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	471	489	1,426	1,433
Segment income	56	55	128	135
(Loss) Income From Discontinued Operations, net of tax	(1)	34	(1)	36
Net income	55	89	127	171
Segment assets	7,765		7,765		$ 7,528
Duke Energy Ohio [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	371	390	1,036	1,053
Duke Energy Ohio [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	90	89	360	358
Duke Energy Ohio [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	10	10	30	22
Duke Energy Ohio [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	461	479	1,396	1,411
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income	50	52	96	107
Segment assets	5,006		5,006
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Segment income	14	12	56	57
Segment assets	2,708		2,708
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Segment income	64	64	152	164
Segment assets	7,714		7,714
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Segment income	(8)	$ (9)	(24)	$ (29)
Segment assets	$ 51		$ 51