Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total		Common Stockholders' Equity [Member]		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]		Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]	Net Gains (Losses) on Cash Flow Hedges [Member]	Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Pension and OPEB Adjustments [Member]	Noncontrolling Interest [Member]		Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member] Member's Equity [Member]	Duke Energy Carolinas [Member] Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]	Duke Energy Carolinas [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member]		Progress Energy [Member] Common Stockholders' Equity [Member]		Progress Energy [Member] Additional Paid-in Capital [Member]	Progress Energy [Member] Retained Earnings [Member]		Progress Energy [Member] Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]	Progress Energy [Member] Net Gains (Losses) on Cash Flow Hedges [Member]	Progress Energy [Member] Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Progress Energy [Member] Pension and OPEB Adjustments [Member]	Progress Energy [Member] Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member] Member's Equity [Member]		Duke Energy Florida [Member] Net Unrealized (Losses) Gains on Available for Sale Securities [Member]		Duke Energy Ohio [Member]		Duke Energy Ohio [Member] Common Stock [Member]	Duke Energy Ohio [Member] Additional Paid-in Capital [Member]		Duke Energy Ohio [Member] Retained Earnings [Member]	Duke Energy Indiana [Member]	Piedmont Natural Gas [Member]	Piedmont Natural Gas [Member] Common Stock [Member]	Piedmont Natural Gas [Member] Retained Earnings [Member]
Beginning Balance at Dec. 31, 2016	$ 41,041		$ 41,033		$ 1	$ 38,741	$ 2,384			$ (20)	$ (1)		$ (72)	$ 8						$ 11,807		$ 11,820		$ 8,094	$ 3,764			$ (23)	$ 1		$ (16)	$ (13)
Beginning Balance, in shares at Dec. 31, 2016					700,000,000
Beginning Balance (member's equity) at Dec. 31, 2016																$ 10,772	$ 10,781		$ (9)														$ 7,358	$ 4,900	$ 4,899		$ 1								$ 4,067
Beginning Balance (parent) at Dec. 31, 2016																																							$ 2,996		$ 762	$ 2,695		$ (461)		$ 1,672	$ 860	$ 812
Net Income	2,361		2,356				2,356							5						821		814			814							7							127
Net income (attributable to parent)	2,356															1,009	1,009			814													547	368	368				127					127	318	76		76
Other comprehensive income (loss)	13		13							1	10		2			1			1	12		12						4	3		5			3			3
Common stock issuances, including dividend reinvestment and employee benefits	33		33			33
Common stock dividends	(1,825)		(1,825)				(1,825)									(625)	(625)			(672)	[1]	(672)	[1]		(672)	[1]							(125)						(25)			(25)			(300)
Distributions to noncontrolling interest in subsidiaries	(2)													(2)
Equitization of certain notes payable to affiliates																				1,047		1,047		1,047
Other	21	[2]	21	[2]			21	[2]								(1)	(1)			2		2		2										3	3											(149)		(149)
Ending Balance at Sep. 30, 2017	41,642		41,631		$ 1	38,774	2,936			$ (19)	9		(70)	11						13,017		13,023		9,143	3,906			$ (19)	4		(11)	(6)
Ending Balance, in shares at Sep. 30, 2017					700,000,000
Ending Balance (member's equity) at Sep. 30, 2017																11,156	11,164		$ (8)														7,780	5,274	5,270		4								4,085
Ending Balance (parent) at Sep. 30, 2017																																							$ 3,098		762	2,670		(334)		$ 1,599	860	739
Beginning Balance at Dec. 31, 2017	$ 41,737		41,739		$ 1	38,792	3,013		$ (10)		12		(69)	(2)						$ 13,465		13,468		9,143	4,350		$ (18)		5		(12)	(3)
Beginning Balance, in shares at Dec. 31, 2017	700,000,000				700,000,000															100																			90,000,000							100
Beginning Balance (member's equity) at Dec. 31, 2017																11,361	11,368	$ (7)															7,949	5,618	5,614		4								4,121
Beginning Balance (parent) at Dec. 31, 2017	$ 41,739																			$ 13,468																			$ 3,163		762	2,670		(269)		$ 1,662	860	802
Net Income	2,190		2,202				2,202							(12)						910		904			904							6
Net income (attributable to parent)	2,202															936	936			904													532	514	514				121					121	317	81		81
Other comprehensive income (loss)	13		13						15		(5)		3			1		1		6		6					5		(1)		2			(1)			(1)
Common stock issuances, including dividend reinvestment and employee benefits, shares					13,000,000
Common stock issuances, including dividend reinvestment and employee benefits	955		955			955
Common stock dividends	(1,914)		(1,914)				(1,914)									(750)	(750)			(250)		(250)			(250)								(175)	(75)	(75)										(175)
Distributions to noncontrolling interest in subsidiaries	(1)													(1)						(1)												(1)
Other	33	[3]					12	[3]			(12)	[3]		33	[3]										5	[4]			(5)	[4]					5	[5]	(5)	[5]	$ 106	[6]		106	[6]			$ 300	300
Ending Balance at Sep. 30, 2018	$ 43,013		$ 42,995		$ 1	$ 39,747	$ 3,313		$ 5		$ (5)		$ (66)	$ 18						$ 14,130		$ 14,128		$ 9,143	$ 5,009		$ (13)		$ (1)		$ (10)	$ 2
Ending Balance, in shares at Sep. 30, 2018	713,000,000				713,000,000															100																			90,000,000							100
Ending Balance (member's equity) at Sep. 30, 2018																$ 11,548	$ 11,554	$ (6)															$ 8,306	$ 6,056	$ 6,058		$ (2)								$ 4,263
Ending Balance (parent) at Sep. 30, 2018	$ 42,995																			$ 14,128																			$ 3,390		$ 762	$ 2,776		$ (148)		$ 2,043	$ 1,160	$ 883

[1] Includes a $547 million non-cash dividend related to a legal entity restructuring.

[2] Cumulative-effect adjustment due to implementation of a new accounting standard related to stock-based compensation and the associated income taxes.

[3] Amounts in Retained Earnings and Accumulated Other Comprehensive Loss represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information. Amount in Noncontrolling Interests relates to tax equity financing activity in the Commercial Renewables segment.

[4] Amounts in Retained Earnings and Accumulated Other Comprehensive Loss represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information.

[5] Amounts in Member's Equity and Accumulated Other Comprehensive Income (Loss) represent a cumulative-effect adjustment due to implementation of a new accounting standard related to Financial Instruments Classification and Measurement. See Note 1 for more information.

[6] Represents a non-cash settlement through equity of an intercompany payable from Duke Energy Ohio to its parent.