Regulatory Matters (Narrative) (Details) $ in Millions																												1 Months Ended				3 Months Ended			6 Months Ended		12 Months Ended
	Jul. 02, 2019 USD ($)	Jun. 13, 2019 USD ($)	May 29, 2019 USD ($)	May 21, 2019 USD ($)	Apr. 02, 2019 USD ($)	Apr. 01, 2019 USD ($)	Mar. 25, 2019 USD ($)	Jan. 30, 2019 USD ($)	Dec. 27, 2018 USD ($)	Nov. 08, 2018 USD ($)	Oct. 30, 2018 USD ($)	Aug. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jun. 22, 2018 USD ($)	May 31, 2018 USD ($)	Apr. 13, 2018 USD ($)	Feb. 28, 2018	Feb. 15, 2018 USD ($)	Nov. 22, 2017	Sep. 27, 2017 USD ($)	Sep. 26, 2017 USD ($)	Aug. 25, 2017 USD ($)	Jun. 01, 2017 USD ($)	Jun. 30, 2016	Dec. 22, 2015	Jan. 05, 2015	Sep. 02, 2014	Nov. 30, 2018 USD ($)	May 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) MW	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jul. 12, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 28, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 31, 2018 customer	Sep. 28, 2018 USD ($)	Mar. 28, 2018 USD ($)	Sep. 30, 2017 customer
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																$ 1,434	$ 1,544		$ 2,853	$ 3,008
Loss before income taxes																																(889)	(607)		(1,877)	(1,410)
Public utilities, property, plant and equipment, net																																97,198			97,198						$ 91,694
Regulated operating revenue, electric, non-nuclear																																5,423	5,178		$ 10,708	10,462
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW																																			5,002
Public utilities, property, plant and equipment, net																																$ 3,217			$ 3,217
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																											47.00%
Long-term purchase commitment, period																											20 years
Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																																24.00%			24.00%
Estimated contributions																																$ 229			$ 229
Equity method investment, OTTI																																				55
Dominion Resources [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																											48.00%
Southern Company Gas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																											5.00%
Williams Partners L.P. [Member] | Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																																41.00%			41.00%
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																																$ 7,000			$ 7,000
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																																7,800			7,800
Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other					$ 553
Estimated capital cost					96
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																441	499		881	950
Loss before income taxes																																(375)	(149)		(731)	(563)
Public utilities, property, plant and equipment, net																																31,202			31,202						29,245
Duke Energy Carolinas [Member] | Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other					171
Estimated capital cost					20
Duke Energy Carolinas [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																		$ 4
Utilities operating expense														$ 150
Penalty assessed														70
Reduction of annual recovery of deferred coal ash costs														$ 14
Requested rate increase (decrease), amount																						$ 647
Requested rate increase, percentage																						13.60%
Requested return on equity, percent																	9.90%
Public utilities, requested equity capital structure, percentage																	52.00%
Public utilities, requested debt capital structure, percentage																	48.00%
Regulatory asset, amortization period														5 years
Loss before income taxes																																		14
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount										$ 168
Requested rate increase, percentage										10.00%
Public utilities, approved equity capital structure, percentage				53.00%
Public utilities, approved debt capital structure, percentage				47.00%
Approved return on equity percentage				9.50%
Change in tax rate, deferred tax liability, income tax benefit				$ 66						$ 66
Measurement period adjustment, income tax expense (benefit)				45						46
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Recovery costs denied				115
Regulatory assets				$ 96						$ 242
Regulatory asset, amortization period				5 years						5 years
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Deferred Project Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets				$ 125
Regulatory asset, amortization period				12 years
Duke Energy Carolinas [Member] | FERC Formula Rate Matter [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Customer refundable fees, refund payments																		$ 25
Duke Energy Carolinas [Member] | 2018 Sale of Hydro Plants [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated loss on asset sale																													$ 40
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																357	375		692	756
Loss before income taxes																																(202)	(174)		(449)	(380)
Public utilities, property, plant and equipment, net																																21,877			$ 21,877						20,398
Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW																																			376
Public utilities, property, plant and equipment, net																																284			$ 284						327
Duke Energy Progress [Member] | Hurricane Florence, Hurricane Michael And Winter Storm Diego Damages [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other					382
Estimated capital cost					$ 76
Duke Energy Progress [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																							$ 477
Requested rate increase, percentage																							14.90%
Requested return on equity, percent																			9.90%
Public utilities, requested equity capital structure, percentage																			52.00%
Public utilities, requested debt capital structure, percentage																			48.00%
Requested rate increase (decrease), amended amount																							$ 420
Requested rate increase (decrease) amended, percentage																							13.00%
Loss before income taxes																																		$ 68
Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount										$ 59
Requested rate increase, percentage										10.30%
Public utilities, approved equity capital structure, percentage				53.00%
Public utilities, approved debt capital structure, percentage				47.00%
Approved return on equity percentage				9.50%
Change in tax rate, deferred tax liability, income tax benefit				$ 17						$ 17
Measurement period adjustment, income tax expense (benefit)				12						10
Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Recovery costs denied				65
Regulatory assets				$ 4						$ 51
Regulatory asset, amortization period				5 years						5 years
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																																												$ 893
Regulatory asset, amortization period																																			10 years
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																244	237		$ 474	474
Loss before income taxes																																(250)	(205)		(369)	(328)
Public utilities, property, plant and equipment, net																																14,388			14,388						13,824
Duke Energy Florida [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																118			118						217
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																																													1,000,000
Operation, maintenance and other		$ 6
Decrease in storm reserve		24
Allowed storm reserve															$ 132														132
Property, plant and equipment, net		$ 18
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance															510														510											$ 508
Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																																										72,000
Estimated storm costs - capital and operation maintenance																																360			360				$ 221
Property, plant and equipment, net																																82			82						35
Duke Energy Florida [Member] | Federal Tax Act Impacts [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax act annual savings									$ 4						134
Tax act excess deferred tax amortization requested rate decrease, amount									71						67
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount															201
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets									$ 155						151														151
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | Crystal River Units 3 and 4 [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, property, plant and equipment, net															$ 50														$ 50
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Hamilton Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount											$ 15
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Columbia Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount													$ 14
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Trenton Generation Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							$ 13
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | Lake Placid Generation Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							8
Duke Energy Florida [Member] | 2017 Second Revised and Restated Stipulation and Settlement Agreement [Member] | DeBary Solar Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							$ 11
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																123	130		255	261
Loss before income taxes																																(56)	(62)		(139)	(25)
Public utilities, property, plant and equipment, net																																7,015			7,015						6,643
Regulated operating revenue, electric, non-nuclear																																336	346		691	682
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																														$ 15
Requested return on equity, percent																														10.40%
Public utilities, requested equity capital structure, percentage																50.75%
Public utilities, requested debt capital structure, percentage																49.25%
Approved rate increase (decrease), amount																$ (20)
Requested rate increase (decrease), amended amount																$ (19)
Requested rate increase (decrease) amended, percentage																9.84%
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																					$ (18)
Requested return on equity, percent																					9.22%
Duke Energy Ohio [Member] | Ohio Base Rate Case 2017 [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount																					$ (29)
Requested return on equity, percent																					10.24%
Requested Rider Revenue Increase																$ 10
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulated operating revenue, electric, non-nuclear																															$ 20
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount																				$ 38
Approved rate increase (decrease), one-time waiver amount																																					$ 56
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | OPSB [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost excluding AFUDC																																163			163
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | OPSB [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost excluding AFUDC																																245			245
Duke Energy Ohio [Member] | MGP Cost Recovery - 2009 Through 2012 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																55			55
Duke Energy Ohio [Member] | MGP Cost Recovery - 2013 Through 2017 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																											$ 26
Duke Energy Ohio [Member] | MGP Cost Recovery - 2013 Through 2017 [Member] | PUCO [Member] | MGP Costs - Regulatory Disallowance [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																											$ 12
Duke Energy Ohio [Member] | MGP Cost Recovery - 2018 [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																20			20
Duke Energy Kentucky [Member] | Duke Energy Kentucky Gas Base Rate Case [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount												$ 11
Requested rate increase, percentage												11.10%
Approved rate increase (decrease), amount								$ 7
Requested rate increase (decrease), amended amount												$ (5)
Approved return on equity percentage								9.70%
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																188	197		377	378
Loss before income taxes																																(128)	(132)		(273)	(267)
Public utilities, property, plant and equipment, net																																10,727			$ 10,727						10,529
Duke Energy Indiana [Member] | 2019 Indiana Rate Case [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Rate base																																									10,200
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage																																			12.38%
Approved return on equity percentage adder																										0.50%
Duke Energy Indiana [Member] | FERC Complaint [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Requested return on equity, percent																																			8.67%
Duke Energy Indiana [Member] | FERC Complaint 1 [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage																									10.32%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | FERC [Member]
Public Utilities, General Disclosures [Line Items]
Requested return on equity, percent																								9.70%
Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																83	85		$ 163	167
Loss before income taxes																																9	$ 11		(147)	$ (134)
Public utilities, property, plant and equipment, net																																6,346			6,346						5,911
Piedmont Natural Gas [Member] | North Carolina Integrity Management Rider Filing [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount			$ 9
Piedmont Natural Gas [Member] | Tennessee Integrity Management Rider Filing November 2018 [Member] | TPUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount																												$ 3
Piedmont Natural Gas [Member] | North Carolina Rate Case 2019 [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						$ 83
Requested rate increase, percentage						9.00%
State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
State and local taxes, increase (reduction), amount				$ (17)						$ (17)
State and Local Jurisdiction [Member] | North Carolina Department of Revenue [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
State and local taxes, increase (reduction), amount				$ 12						$ 12
Subsequent Event [Member] | Duke Energy Ohio [Member] | MGP Cost Recovery - 2018 [Member] | PUCO [Member] | MGP Costs - Regulatory Disallowance [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																																						$ 11
Subsequent Event [Member] | Duke Energy Indiana [Member] | 2019 Indiana Rate Case [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 395
Requested rate increase, percentage	15.00%
Noncurrent Assets, Other [Member] | Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance																																$ 225			$ 225						$ 165