Regulatory Matters (Narrative) (Details) $ in Millions																								1 Months Ended			3 Months Ended
	May 08, 2019 USD ($)	May 01, 2019 USD ($)	Apr. 30, 2019 USD ($)	Apr. 09, 2019 USD ($)	Apr. 02, 2019 USD ($)	Apr. 01, 2019 USD ($)	Mar. 25, 2019 USD ($)	Jan. 30, 2019 USD ($)	Dec. 27, 2018 USD ($)	Nov. 08, 2018 USD ($)	Aug. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	May 31, 2018 USD ($)	Feb. 28, 2018	Feb. 15, 2018 USD ($)	Nov. 22, 2017	Sep. 27, 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 ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2019 USD ($) MW	Mar. 31, 2018 USD ($)	Jan. 28, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 31, 2018 USD ($) customer	Sep. 28, 2018 USD ($)	Mar. 28, 2018 USD ($)	Sep. 30, 2017 customer
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																											$ 1,419	$ 1,464
Loss before income taxes																											(988)	(803)
Public utilities, property, plant and equipment, net																											95,721			$ 91,694
Regulated operating revenue, electric, non-nuclear																											$ 5,285	5,284
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Capacity (in MW) | MW																											865
Public utilities, property, plant and equipment, net																											$ 279
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%
Estimated contributions																											$ 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%
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																											$ 7,000
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																											7,800
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																											440	451
Loss before income taxes																											(356)	(414)
Public utilities, property, plant and equipment, net																											31,030			29,245
Duke Energy Carolinas [Member] | 2017 North Carolina Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																												4
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%
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%
Change in tax rate, deferred tax liability, income tax benefit										$ 66
Measurement period adjustment, income tax expense (benefit)										(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]
Regulatory assets										$ 242
Regulatory asset, amortization period										5 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																											335	381
Loss before income taxes																											(247)	(206)
Public utilities, property, plant and equipment, net																											$ 21,889			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																											$ 302			327
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%
Measurement period adjustment, income tax expense (benefit)										$ (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]
Regulatory assets										$ 51
Regulatory asset, amortization period										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																											$ 230	237
Loss before income taxes																											(119)	(123)
Public utilities, property, plant and equipment, net																											14,108			13,824
Duke Energy Florida [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																											157			217
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]
Public Utilities, General Disclosures [Line Items]
Customers experiencing outages | customer																																		1,000,000
Allowed storm reserve													$ 132												132
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																											213			165	$ 360
Property, plant and equipment, net																											70			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																											132	131
Loss before income taxes																											(83)	37
Public utilities, property, plant and equipment, net																											6,803			6,643
Regulated operating revenue, electric, non-nuclear																											355	336
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
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
Duke Energy Ohio [Member] | MGP Cost Recovery [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																											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 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)
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																											189	181
Loss before income taxes																											(145)	(135)
Public utilities, property, plant and equipment, net																											$ 10,612			10,529
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																											$ 80	82
Loss before income taxes																											(156)	$ (145)
Public utilities, property, plant and equipment, net																											$ 6,089			$ 5,911
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
Subsequent Event [Member] | 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
Subsequent Event [Member] | 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
Subsequent Event [Member] | Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved equity capital structure, percentage		53.00%
Public utilities, approved debt capital structure, percentage		47.00%
Approved rate increase (decrease), amount		$ 107
Approved return on equity percentage		9.50%
Subsequent Event [Member] | 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
Subsequent Event [Member] | 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
Subsequent Event [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved equity capital structure, percentage	53.00%
Public utilities, approved debt capital structure, percentage	47.00%
Approved rate increase (decrease), amount	$ 41
Approved return on equity percentage	9.50%
Subsequent Event [Member] | 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
Subsequent Event [Member] | 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%
North Carolina Department of Revenue [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Measurement period adjustment, income tax expense (benefit)										$ (17)
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, reduction, amount										(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, reduction, amount										$ (12)
Scenario, Forecast [Member] | Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other				$ (6)
Allowed storm reserve				24
Property, plant and equipment, net				$ 18
Scenario, Forecast [Member] | Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Estimated storm costs - capital and operation maintenance			$ 221
Estimated storm costs - anticipated recovery period			12 months