Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [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] 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] 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	717				716						716		1				201				199						199		2
Net income (attributable to parent)	716													270	270		199													147	90	90				42			42	91	95		95
Other comprehensive income (loss)	8						3	4		1	8						3						1	1		1	3				1			1
Common stock issuances, including dividend reinvestment and employee benefits, shares			0
Common stock issuances, including dividend reinvestment and employee benefits	1			1							1
Distributions to noncontrolling interest in subsidiaries	(2)												(2)
Distributions/dividends to parent	(600)				(600)						(600)			(175)	(175)
Other	21	[1]			21	[1]					21	[1]					1		0								0		1
Ending Balance at Mar. 31, 2017	41,186		$ 1	38,742	2,521		(17)	3		(71)	41,179		7				12,012		8,094		3,963		(22)	2		(15)	12,022		(10)
Ending Balance, in shares at Mar. 31, 2017			700,000,000
Ending Balance (member's equity) at Mar. 31, 2017														10,867	10,876	(9)														7,505	4,991	4,989		2						4,158
Ending Balance (parent) at Mar. 31, 2017																																				$ 3,038	762	2,695	(419)		$ 1,767	860	907
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	622				620						620		2				237				235						235		2
Net income (attributable to parent)	620													323	323		235													177	103	103				$ (25)			(25)	100	$ 110		110
Other comprehensive income (loss)	11						13	(3)		1	11			1		1	2						2				2
Common stock issuances, including dividend reinvestment and employee benefits, shares			1,000,000
Common stock issuances, including dividend reinvestment and employee benefits	47			47							47
Distributions to noncontrolling interest in subsidiaries	(1)												(1)
Distributions/dividends to parent	(625)				(625)						(625)			(250)	(250)
Other	7				13	[2]		(13)	[2]				7				(1)	[2]	(1)	[2]	6	[2]		(6)	[2]		(1)	[2]				6	[3]	(6)	[3]
Ending Balance at Mar. 31, 2018	$ 41,798		$ 1	$ 38,839	$ 3,021		$ 3	$ (4)		$ (68)	$ 41,792		$ 6				$ 13,703		$ 9,142		$ 4,591		$ (16)	$ (1)		$ (12)	$ 13,704		$ (1)
Ending Balance, in shares at Mar. 31, 2018	701,000,000		701,000,000														100																			90,000,000					100
Ending Balance (member's equity) at Mar. 31, 2018														$ 11,435	$ 11,441	$ (6)														$ 8,126	$ 5,721	$ 5,723		$ (2)						$ 4,221
Ending Balance (parent) at Mar. 31, 2018	$ 41,792																$ 13,704																			$ 3,138	$ 762	$ 2,670	$ (294)		$ 1,772	$ 860	$ 912

[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.