Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total		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 Gains (Losses) on Available for Sale Securities [Member]		Pension and OPEB Adjustments [Member]	Common Stockholders' Equity [Member]		Noncontrolling Interest [Member]	Duke Energy Carolinas [Member]	Duke Energy Carolinas [Member] Members 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] 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 Gains (Losses) on Available for Sale Securities [Member]		Progress Energy [Member] Pension and OPEB Adjustments [Member]	Progress Energy [Member] Common Stockholders' Equity [Member]	Progress Energy [Member] Noncontrolling Interest [Member]	Duke Energy Progress [Member]	Duke Energy Florida [Member]	Duke Energy Florida [Member] Members Equity [Member]		Duke Energy Florida [Member] Net Unrealized Gains (Losses) 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		$ 1	$ 38,741	$ 2,384			$ (20)	$ (1)		$ (72)	$ 41,033		$ 8					$ 11,807	$ 8,094	$ 3,764			$ (23)	$ 1		$ (16)	$ 11,820	$ (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	1,406				1,402							1,402		4					478		473							473	5
Net income (attributable to parent)	1,402														543	543			473											301	248	248				72					72	197	87		87
Other comprehensive income (loss)	11							1	8		2	11			1			1	10					6	2		2	10			2			2
Common stock issuances, including dividend reinvestment and employee benefits	17			17								17
Common stock dividends	(1,200)				(1,200)							(1,200)			(375)	(375)																				(25)			(25)			(150)
Distributions to noncontrolling interest in subsidiaries	(2)													(2)
Other	21	[1]			21	[1]						21	[1]		(2)	(2)			2	2								2	0		2	2											(149)		(149)
Ending Balance at Jun. 30, 2017	41,294		$ 1	38,758	2,607			$ (19)	7		(70)	41,284		10					12,297	8,096	4,237			$ (17)	3		(14)	12,305	(8)
Ending Balance, in shares at Jun. 30, 2017			700,000,000
Ending Balance (member's equity) at Jun. 30, 2017															10,939	10,947		$ (8)												7,659	5,152	5,149		3								4,114
Ending Balance (parent) at Jun. 30, 2017																																				$ 3,043		762	2,670		(389)		$ 1,610	860	750
Beginning Balance at Dec. 31, 2017	$ 41,737		$ 1	38,792	3,013		$ (10)		12		(69)	41,739		(2)					$ 13,465	9,143	4,350		$ (18)		5		(12)	13,468	(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	1,124				1,120							1,120		4					504		500							500	4
Net income (attributable to parent)	1,120														440	440			500											316	271	271				21					21	198	102		102
Other comprehensive income (loss)	9						12		(5)		2	9			1		1		4				3		(1)		2	4			(1)			(1)
Common stock issuances, including dividend reinvestment and employee benefits, shares			12,000,000
Common stock issuances, including dividend reinvestment and employee benefits	890			890								890
Common stock dividends	(1,251)				(1,251)							(1,251)			(500)	(500)																										(75)
Distributions to noncontrolling interest in subsidiaries	(1)													(1)					(1)										$ (1)
Other	7				12	[2]			(12)	[2]				7							5	[2]			(5)	[2]						5	[3]	(5)	[3]	$ 106	[4]		106	[4]			$ 300	300
Ending Balance at Jun. 30, 2018	$ 42,515		$ 1	$ 39,682	$ 2,894		$ 2		$ (5)		$ (67)	$ 42,507		$ 8					$ 13,972	$ 9,143	$ 4,855		$ (15)		$ (1)		$ (10)	$ 13,972
Ending Balance, in shares at Jun. 30, 2018	712,000,000		712,000,000																100																	90,000,000							100
Ending Balance (member's equity) at Jun. 30, 2018															$ 11,302	$ 11,308	$ (6)													$ 8,265	$ 5,888	$ 5,890		$ (2)								$ 4,244
Ending Balance (parent) at Jun. 30, 2018	$ 42,507																		$ 13,972																	$ 3,290		$ 762	$ 2,776		$ (248)		$ 2,064	$ 1,160	$ 904

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

[2] 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.

[3] 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.

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