Business Segments (Business Segment Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Unaffiliated revenues	$ 5,555	$ 5,213	$ 11,284	$ 10,590
Operating revenues	5,555	5,213	11,284	10,590
Segment income	688	624	1,404	1,198
Add back noncontrolling interests	3		4	3
(Loss) Income From Discontinued Operations, net of tax	(2)	(112)	(2)	10
Net income	689	512	1,406	1,211
Net income	686	509	1,402	1,203
Segment assets	135,004		135,004		$ 132,761
Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	5,150	4,993	10,090	10,074
Operating revenues	5,158	5,001	10,105	10,090
Segment income	729	704	1,364	1,368
Segment assets	117,009		117,009
Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	279	97	927	266
Operating revenues	301	99	971	269
Segment income	27	16	160	48
Segment assets	11,073		11,073
Operating Segments [Member] | Commercial Renewables [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	110	112	238	226
Operating revenues	110	112	238	226
Segment income	26	11	51	37
Segment assets	4,306		4,306
Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	5,539	5,202	11,255	10,566
Operating revenues	5,569	5,212	11,314	10,585
Segment income	782	731	1,575	1,453
Segment assets	132,388		132,388
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	(49)	(29)	(98)	(54)
Segment assets	181		181
Intersegment Eliminations [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	8	15	16
Intersegment Eliminations [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	22	2	44	3
Intersegment Eliminations [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	19	19	39	35
Intersegment Eliminations [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	30	10	59	19
Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Unaffiliated revenues	16	11	29	24
Operating revenues	35	30	68	59
Segment income	(94)	(107)	(171)	(255)
Segment assets	2,435		2,435
Duke Energy Ohio [Member]
Segment Reporting Information [Line Items]
Operating revenues	437	428	955	944
Segment income	30	23	72	80
(Loss) Income From Discontinued Operations, net of tax				2
Net income	30	23	72	82
Segment assets	7,605		7,605		$ 7,528
Duke Energy Ohio [Member] | Operating Segments [Member] | Electric Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	329	323	665	663
Segment income	22	19	46	55
Segment assets	4,879		4,879
Duke Energy Ohio [Member] | Operating Segments [Member] | Gas Utilities and Infrastructure [Member]
Segment Reporting Information [Line Items]
Operating revenues	100	98	270	269
Segment income	17	14	42	45
Segment assets	2,672		2,672
Duke Energy Ohio [Member] | Operating Segments [Member] | Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	429	421	935	932
Segment income	39	33	88	100
Segment assets	7,551		7,551
Duke Energy Ohio [Member] | Corporate, Non-Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating revenues	8	7	20	12
Segment income	(9)	$ (10)	(16)	$ (20)
Segment assets	$ 54		$ 54