Regulatory Matters (Narrative) (Details) $ in Millions																												1 Months Ended											2 Months Ended	3 Months Ended				12 Months Ended
	Jan. 30, 2019 USD ($)	Dec. 27, 2018 USD ($)	Nov. 08, 2018 USD ($)	Oct. 03, 2018	Sep. 20, 2018 USD ($)	Aug. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jul. 25, 2018 USD ($)	Jul. 10, 2018 USD ($)	Jun. 27, 2018 USD ($)	Jun. 22, 2018 USD ($)	Jun. 08, 2018 USD ($)	May 31, 2018 USD ($)	Apr. 13, 2018 USD ($)	Apr. 01, 2018 USD ($)	Feb. 15, 2018 USD ($)	Sep. 27, 2017 USD ($)	Sep. 26, 2017 USD ($)	Sep. 01, 2017 USD ($)	Aug. 25, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 01, 2017 USD ($)	Jun. 30, 2016	Dec. 22, 2015	May 04, 2015 USD ($)	Jan. 05, 2015	Sep. 02, 2014	Jan. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) customer	Nov. 30, 2018 USD ($)	Oct. 31, 2018 USD ($) customer	Sep. 30, 2018 USD ($) customer	Jul. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	May 31, 2018 USD ($)	Feb. 28, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($) customer	Sep. 30, 2018 USD ($) customer	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) customer MW	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2016 USD ($)	Jan. 29, 2019 USD ($)	Sep. 30, 2017 USD ($)	Oct. 02, 2014 USD ($)
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													$ 91,694.0											$ 91,694.0				$ 91,694.0	$ 86,391.0
Regulatory assets, noncurrent																													13,617.0											13,617.0				13,617.0	12,442.0
Net property, plant and equipment																													91,694.0											91,694.0				91,694.0	86,391.0
Operation, maintenance and other																																												6,463.0	5,944.0	$ 6,224.0
Regulatory assets																													15,622.0											15,622.0				15,622.0	13,879.0
Total income (loss) from continuing operations before income taxes																																												(3,073.0)	(4,266.0)	(3,734.0)
Impairment charges																																												402.0	282.0	18.0
Regulated Revenue																																												22,097.0	21,177.0	21,221.0
Asset Impairment Charges																																												402.0	282.0	18.0
Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment																													$ 283.0											$ 283.0				$ 283.0
Capacity (in MW) | MW																																												865
Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																											47.00%
Long-term Purchase Commitment, Period																											20 years
Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																									7.50%
Estimated capital cost																									$ 3,200.0
Long-term Purchase Commitment, Period																									25 years
Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																													24.00%											24.00%				24.00%
Estimated Contributions																													$ 229.0											$ 229.0				$ 229.0
Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													4,255.0											4,255.0				4,255.0	4,025.0
Regulatory Clause Revenues, under-recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													24.0											24.0				24.0	64.0
Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													2,654.0											2,654.0				2,654.0	2,249.0
Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													445.0											445.0				445.0	480.0
NCEMPA deferrals [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													50.0											50.0				50.0	53.0
Nuclear asset securitized balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													1,093.0											1,093.0				1,093.0	1,142.0
Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													133.0											133.0				133.0	119.0
Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													1,117.0											1,117.0				1,117.0	531.0
Minimum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																													7,000.0											7,000.0				7,000.0
Maximum [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost																													$ 7,800.0											$ 7,800.0				$ 7,800.0
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%
Enbridge Inc. [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																									50.00%
NextEra Energy [Member] | Sabal Trail Transmission Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																									42.50%
Williams Partners L.P. [Member] | Constitution Pipeline [Member]
Public Utilities, General Disclosures [Line Items]
Joint owner ownership percentage																													41.00%											41.00%				41.00%
Hurricane Florence Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers Experiencing Outages | customer																																2,000,000									2,000,000
Operation, maintenance and other																																$ 500.0
Estimated capital cost																																90.0									$ 90.0
Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers Experiencing Outages | customer																															1,000,000
Operation, maintenance and other																															$ 100.0
Estimated capital cost																															21.0
Winter Storm Diego Damage [Member]
Public Utilities, General Disclosures [Line Items]
Customers Experiencing Outages | customer																													800,000											800,000				800,000
Operation, maintenance and other																													$ 85.0
Estimated capital cost																													9.0											$ 9.0				$ 9.0
Progress Energy Merger FERC Mitigation [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Penalty assessed												$ 3.5
Duke Energy Carolinas [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													29,245.0											29,245.0				29,245.0	27,876.0
Regulatory assets, noncurrent																													3,457.0											3,457.0				3,457.0	2,853.0
Net property, plant and equipment																													29,245.0											29,245.0				29,245.0	27,876.0
Operation, maintenance and other																																												2,130.0	2,021.0	2,158.0
Regulatory assets																													3,977.0											3,977.0				3,977.0	3,152.0
Total income (loss) from continuing operations before income taxes																																												(1,374.0)	(1,866.0)	(1,800.0)
Impairment charges																																												192.0		1.0
Asset Impairment Charges																																												192.0		1.0
Duke Energy Carolinas [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Long-term Purchase Commitment, Period																											20 years
Duke Energy Carolinas [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													1,725.0											1,725.0				1,725.0	1,645.0
Duke Energy Carolinas [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													581.0											581.0				581.0	410.0
Duke Energy Carolinas [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													21.0											21.0				21.0	29.0
Duke Energy Carolinas [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													87.0											87.0				87.0	84.0
Duke Energy Carolinas [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													160.0											160.0				160.0
Duke Energy Carolinas [Member] | William States Lee Combined Cycle Facility [Member] | NCEMC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC																													$ 650.0											$ 650.0				$ 650.0
Joint owner ownership percentage																													13.00%											13.00%				13.00%
Approved rate increase (decrease) amount by state commission																																												$ 600.0
Duke Energy Carolinas [Member] | Hurricane Florence Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																70.0
Estimated capital cost																																5.0									5.0
Duke Energy Carolinas [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																															75.0
Estimated capital cost																															12.0
Duke Energy Carolinas [Member] | Winter Storm Diego Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																													$ 60.0
Estimated capital cost																													7.0											$ 7.0				7.0
Duke Energy Carolinas [Member] | 2017 NC Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																				$ 647.0
Requested Rate Increase (Decrease), Percentage																				13.60%
Requested Return on Equity, Percentage																																				9.90%
Public Utilities, Requested Equity Capital Structure, Percentage																																				52.00%
Public Utilities, Requested Debt Capital Structure, Percentage																																				48.00%
Operation, maintenance and other																																				$ 4.0
Total income (loss) from continuing operations before income taxes																																											$ 14.0
Penalty assessed											$ 70.0
Estimated future coal ash costs											201.0
Utilities Operating Expense											150.0
Duke Energy Carolinas [Member] | 2017 NC Rate Case [Member] | NCUC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets											$ 554.0
Regulatory Noncurrent Asset, Amortization Period											5 years
Duke Energy Carolinas [Member] | 2017 NC Rate Case [Member] | NCUC [Member] | Deferred Project Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets											$ 347.0
Regulatory Noncurrent Asset, Amortization Period											12 years
Duke Energy Carolinas [Member] | 2017 NC Rate Case [Member] | William State Lee III Nuclear Station [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Utilities Operating Expense																																										$ 29.0
Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount			$ 168.0
Requested Rate Increase (Decrease), Percentage			10.00%
Tax benefit from change in enacted tax rates			$ 66.0
Tax benefits from Tax Act			46.0
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			$ 242.0
Regulatory Noncurrent Asset, Amortization Period			5 years
Duke Energy Carolinas [Member] | FERC Formula Rate Matter [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Customer Refundable Fees, Refund Payments																$ 25.0
Duke Energy Carolinas [Member] | 2018 PSCSC Petitions [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission								$ 33.0
Duke Energy Carolinas [Member] | 2018 Sale of Hydro Plants [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Estimated loss on Asset Sale																																			$ 40.0
Duke Energy Progress [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													20,398.0											20,398.0				20,398.0	19,101.0
Regulatory assets, noncurrent																													4,111.0											4,111.0				4,111.0	3,507.0
Net property, plant and equipment																													20,398.0											20,398.0				20,398.0	19,101.0
Operation, maintenance and other																																												1,578.0	1,439.0	1,565.0
Regulatory assets																													4,814.0											4,814.0				4,814.0	3,859.0
Total income (loss) from continuing operations before income taxes																																												(827.0)	(1,007.0)	(900.0)
Impairment charges																																												33.0	19.0	1.0
Asset Impairment Charges																																												33.0	19.0	1.0
Duke Energy Progress [Member] | Atlantic Coast Pipeline (ACP) [Member]
Public Utilities, General Disclosures [Line Items]
Long-term Purchase Commitment, Period																											20 years
Duke Energy Progress [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													2,051.0											2,051.0				2,051.0	1,975.0
Duke Energy Progress [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													542.0											542.0				542.0	430.0
Duke Energy Progress [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													148.0											148.0				148.0	170.0
Duke Energy Progress [Member] | NCEMPA deferrals [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													50.0											50.0				50.0	53.0
Duke Energy Progress [Member] | Nuclear Deferral [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													46.0											46.0				46.0	35.0
Duke Energy Progress [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													571.0											571.0				571.0	150.0
Duke Energy Progress [Member] | Asheville Plant [Member] | Generation Facilities To Be Retired [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment																													327.0											327.0				$ 327.0	385.0
Capacity (in MW) | MW																																												376
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets, noncurrent																													43.0											43.0				$ 43.0
Wholesale Debt Return Amortization Period																																												15 years
Regulatory Noncurrent Asset, Amortization Period																																												8 years
Duke Energy Progress [Member] | Hurricane Florence Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																																430.0
Estimated capital cost																																$ 85.0									85.0
Duke Energy Progress [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																															25.0
Estimated capital cost																															$ 9.0
Duke Energy Progress [Member] | Winter Storm Diego Damage [Member]
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other																													25.0
Estimated capital cost																													2.0											2.0				$ 2.0
Duke Energy Progress [Member] | 2017 NC Rate Case [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																						$ 477.0
Requested Rate Increase (Decrease), Percentage																						14.90%
Requested Rate Increase (Decrease), Amended, Amount																						$ 420.0
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage																						13.00%
Requested Return on Equity, Percentage																																												9.90%
Public Utilities, Requested Equity Capital Structure, Percentage																																												52.00%
Public Utilities, Requested Debt Capital Structure, Percentage																																												48.00%
Utilities Operating Expense, Impairments																																													25.0
Estimated Storm Costs - Capital and Operation Maintenance																																																	$ 116.0
Total income (loss) from continuing operations before income taxes																																											$ 68.0
Penalty assessed																																												$ 30.0
Estimated future coal ash costs																													129.0											129.0				129.0
Duke Energy Progress [Member] | 2017 NC Rate Case [Member] | NCUC [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													234.0											234.0				$ 234.0
Regulatory Noncurrent Asset, Amortization Period																																												5 years
Excluded Deferred Coal Ash Costs																													10.0											10.0				$ 10.0
Duke Energy Progress [Member] | 2017 NC Rate Case [Member] | NCUC [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																																												80.0
Approved rate increase (decrease) amount by state commission																																												$ 51.0
Regulatory Noncurrent Asset, Amortization Period																																												5 years
Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount			$ 59.0
Requested Rate Increase (Decrease), Percentage			10.30%
Tax benefit from change in enacted tax rates			$ 15.0
Tax benefits from Tax Act			10.0
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			$ 51.0
Regulatory Noncurrent Asset, Amortization Period			5 years
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																												$ 56.0
Approved return on equity percentage amount by state commission																																												10.10%
Regulatory Noncurrent Asset, Amortization Period																																												15 years
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 1 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																												$ 38.0
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 2 Increase [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																												$ 19.0
Duke Energy Progress [Member] | 2016 South Carolina Rate Case Settlement Year 2 Offset [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																													(19.0)
Duke Energy Progress [Member] | Western Carolinas Modernization Plan [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory Noncurrent Asset, Amortization Period																																												10 years
Estimated capital cost																													893.0											893.0				$ 893.0
Duke Energy Progress [Member] | 2018 PSCSC Petitions [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																	$ 20.0
Duke Energy Progress [Member] | FERC Form 1 Reporting Matter [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Customer Refundable Fees, Refund Payments																																												14.0
Duke Energy Florida [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													13,824.0											13,824.0				13,824.0	12,783.0
Regulatory assets, noncurrent																													2,454.0											2,454.0				2,454.0	2,503.0
Net property, plant and equipment																													13,824.0											13,824.0				13,824.0	12,783.0
Operation, maintenance and other																																												1,025.0	853.0	884.0
Regulatory assets																													2,888.0											2,888.0				2,888.0	2,892.0
Total income (loss) from continuing operations before income taxes																																												(655.0)	(758.0)	(873.0)
Impairment charges																																												54.0	138.0	6.0
Asset Impairment Charges																																												54.0	138.0	6.0
Duke Energy Florida [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													10.0											10.0				10.0	9.0
Duke Energy Florida [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													532.0											532.0				532.0	476.0
Duke Energy Florida [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													219.0											219.0				219.0	216.0
Duke Energy Florida [Member] | Nuclear asset securitized balance, net [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													1,093.0											1,093.0				1,093.0	1,142.0
Duke Energy Florida [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													382.0											382.0				382.0	376.0
Duke Energy Florida [Member] | Citrus County Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC																																																		$ 1,500.0
Impairment charges																																								60.0
Asset Impairment Charges																																								60.0
Duke Energy Florida [Member] | Citrus County Combined Cycle Facility [Member] | Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Estimated capital cost of new utility plant, including AFUDC																												$ 1,600.0
Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member]
Public Utilities, General Disclosures [Line Items]
Net property, plant and equipment																													35.0											35.0				35.0
Customers Experiencing Outages | customer																															72,000
Estimated Storm Costs - Capital and Operation Maintenance																													165.0		$ 200.0									165.0				165.0
Duke Energy Florida [Member] | Hurricane Michael Storm Damage [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													$ 165.0											$ 165.0				$ 165.0
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member]
Public Utilities, General Disclosures [Line Items]
Customers Experiencing Outages																													1,000,000											1,000,000				1,000,000
Estimated Storm Costs - Capital and Operation Maintenance																													$ 510.0											$ 510.0				$ 510.0
Regulatory assets																													217.0											217.0				217.0
Allowed Storm Reserve																													$ 132.0											$ 132.0				$ 132.0
Duke Energy Florida [Member] | Storm Restoration Cost Recovery [Member] | Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Storm Costs - Capital and Operation Maintenance																																																$ 508.0
Duke Energy Florida [Member] | Federal Tax Act Impacts [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax Act Annual Tax Savings Requested Rate Decrease, Amount		$ 4.0											$ 134.0
Tax Act Excess Deferred Tax Amortization Requested Rate Decrease, Amount		67.0											67.0
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount		$ 71.0											201.0
Duke Energy Florida [Member] | Federal Tax Act Impacts Revenue Requirement [Member] | FPSC [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets													151.0																						151.0
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													$ 50.0																						$ 50.0
Duke Energy Florida [Member] | Citrus County Combined Cycle Facility [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission									$ 200.0
Duke Energy Florida [Member] | Second Revised And Restated Stipulation And Settlement Agreement 2017 [Member] | Hamilton Project [Member] | Subsequent Event [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																												$ (15.0)
Duke Energy Florida [Member] | Second Revised And Restated Stipulation And Settlement Agreement 2017 [Member] | Columbia Project [Member] | FPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount							$ (14.0)
Duke Energy Ohio [Member]
Public Utilities, General Disclosures [Line Items]
Limit of Total Capital																													30.00%											30.00%				30.00%
Public Utilities, Property, Plant and Equipment, Net																													$ 6,643.0											$ 6,643.0				$ 6,643.0	6,041.0
Regulatory assets, noncurrent																													531.0											531.0				531.0	445.0
Net property, plant and equipment																													6,643.0											6,643.0				6,643.0	6,041.0
Operation, maintenance and other																																												480.0	530.0	514.0
Regulatory assets																													564.0											564.0				564.0	494.0
Total income (loss) from continuing operations before income taxes																																												(219.0)	(252.0)	(270.0)
Impairment charges																																													1.0
Regulated Revenue																																												1,450.0	1,373.0	1,410.0
Asset Impairment Charges																																													1.0
Duke Energy Ohio [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													20.0											20.0				20.0	17.0
Duke Energy Ohio [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													146.0											146.0				146.0	139.0
Duke Energy Ohio [Member] | Storm Costs [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													4.0											4.0				4.0	5.0
Duke Energy Ohio [Member] | RTO Realignment [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													43.0											43.0				43.0	50.0
Duke Energy Ohio [Member] | Electric Base Rate Case [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																																					$ 15.0
Requested Rate Increase (Decrease), Amended, Amount														$ (19.0)
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage														9.84%
Requested Return on Equity, Percentage																																					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 by state commission															$ (20.0)
Duke Energy Ohio [Member] | Electric Base Rate Case [Member] | PUCO [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																		$ (18.0)
Requested Return on Equity, Percentage																		9.22%
Duke Energy Ohio [Member] | Electric Base Rate Case [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																		$ (29.0)
Requested Return on Equity, Percentage																		10.24%
Requested Rider Revenue Increase														$ 10.0
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | Ohio Power Siting Board [Member] | Minimum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC																													163.0											163.0				163.0
Duke Energy Ohio [Member] | Natural Gas Pipeline Extension [Member] | Ohio Power Siting Board [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Capital Cost Excluding AFUDC																													245.0											245.0				245.0
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery Program [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																													56.0
Regulated Revenue																																						$ 20.0
Duke Energy Ohio [Member] | Energy Efficiency Cost Recovery Program [Member] | PUCO [Member] | Maximum [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																	$ 38.0
Duke Energy Ohio [Member] | Mgp Remediation [Member] | East End Site [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													24.0											24.0				24.0
Duke Energy Ohio [Member] | Mgp Remediation [Member] | West End Site [Member] | PUCO [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													$ 23.0											$ 23.0				23.0
Duke Energy Ohio [Member] | FERC 494 Refund Of Regional Transmission Enhancement Projects [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Customer Refundable Fees, Refund Payments																																												$ 47.0
Duke Energy Kentucky [Member]
Public Utilities, General Disclosures [Line Items]
Required Equity Capital Structure Percent																													35.00%											35.00%				35.00%
Duke Energy Kentucky [Member] | Duke Energy Kentucky Electric Rate Case [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																			$ 49.0
Requested Rate Increase (Decrease), Percentage																			15.00%
Requested Rate Increase (Decrease), Amended, Amount																			$ (30.1)
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage																			9.00%
Approved rate increase (decrease) amount by state commission														$ 8.0
Approved return on equity percentage amount by state commission														9.725%
Public Utilities, Approved Equity Capital Structure, Percentage														49.00%
Total Allocable Capitalization														$ 650.0
Incremental Rider Revenue														$ 13.0
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						$ 11.0
Requested Rate Increase (Decrease), Percentage						11.10%
Requested Rate Increase (Decrease), Amended, Amount						$ (5.0)
Duke Energy Kentucky [Member] | Duke Energy Kentucky Gas Base Rate Case [Member] | Subsequent Event [Member] | KPSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission	$ 7.0
Duke Energy Kentucky [Member] | FERC 494 Refund Of Regional Transmission Enhancement Projects [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Customer Refundable Fees, Refund Payments																																												$ 47.0
Duke Energy Indiana [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													$ 10,529.0											$ 10,529.0				10,529.0	10,286.0
Regulatory assets, noncurrent																													982.0											982.0				982.0	978.0
Net property, plant and equipment																													10,529.0											10,529.0				10,529.0	10,286.0
Operation, maintenance and other																																												788.0	743.0	727.0
Regulatory assets																													1,157.0											1,157.0				1,157.0	1,143.0
Total income (loss) from continuing operations before income taxes																																												(521.0)	(655.0)	(606.0)
Impairment charges																																												30.0	18.0	8.0
Asset Impairment Charges																																												30.0	18.0	$ 8.0
Duke Energy Indiana [Member] | Asset retirement obligations - coal ash [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													450.0											450.0				450.0	380.0
Duke Energy Indiana [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													222.0											222.0				222.0	197.0
Duke Energy Indiana [Member] | Retired Generation Facilities [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													57.0											57.0				$ 57.0	65.0
Duke Energy Indiana [Member] | Edwardsport Integrated Gasification Combined Cycle Plant [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission					$ (10.0)
Impairment charges																																									32.0
Regulatory assets, net increase (decrease)					$ (30.0)
Asset Impairment Charges																																									$ 32.0
Duke Energy Indiana [Member] | Benton County Wind Farm Dispute [Member]
Public Utilities, General Disclosures [Line Items]
Litigation Settlement, Amount Awarded to Other Party																					$ 29.0
Duke Energy Indiana [Member] | FERC Transmission Rates [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission																																												12.38%
Approved Return on Equity Percentage Adder																										0.50%
Duke Energy Indiana [Member] | FERC Complaint [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage																																												8.67%
Duke Energy Indiana [Member] | FERC Complaint 1 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission																								10.32%
Duke Energy Indiana [Member] | FERC Complaint 2 [Member] | Federal Energy Regulatory Commission [Member]
Public Utilities, General Disclosures [Line Items]
Requested Return on Equity, Percentage																							9.70%
Duke Energy Indiana [Member] | Federal Tax Act Impacts Tranche 1 [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount										$ (7.0)
Duke Energy Indiana [Member] | Federal Tax Act Impacts Tranche 2 [Member] | IURC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount										$ (35.0)
Piedmont Natural Gas [Member]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Property, Plant and Equipment, Net																													5,911.0											5,911.0				$ 5,911.0	5,246.0
Regulatory assets, noncurrent																													303.0											303.0				303.0	283.0
Net property, plant and equipment																													5,911.0											5,911.0				5,911.0	5,246.0
Operation, maintenance and other																																							$ 50.0					357.0	304.0		$ 353.0
Regulatory assets																													357.0											357.0				357.0	378.0
Total income (loss) from continuing operations before income taxes																																							$ (86.0)					(166.0)	(201.0)		$ (317.0)
Impairment charges																																													7.0
Asset Impairment Charges																																													7.0
Piedmont Natural Gas [Member] | Regulatory Clause Revenues, under-recovered [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													24.0											24.0				24.0	64.0
Piedmont Natural Gas [Member] | Accrued Pension And Post Retirement [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory assets																													$ 99.0											$ 99.0				$ 99.0	$ 91.0
Piedmont Natural Gas [Member] | South Carolina Rate Stabilization Adjustment Filing [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Approved return on equity percentage amount by state commission				10.20%
Piedmont Natural Gas [Member] | NCUC IMR Petition Filed October 2017 [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Requested Rate Increase (Decrease), Amount																															$ 10.0
Piedmont Natural Gas [Member] | NCUC IMR Petition Filed May 2017 [Member] | NCUC [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease) amount by state commission																																		$ 6.0
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 by state commission																														$ 3.0
North Carolina Department of Revenue [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax benefits from Tax Act			$ 17.0
North Carolina Department of Revenue [Member] | State [Member] | Duke Energy Carolinas [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax benefit from reduction in state taxes			(17.0)
North Carolina Department of Revenue [Member] | State [Member] | Duke Energy Progress [Member] | South Carolina Rate Case 2018 [Member] | PSCSC [Member]
Public Utilities, General Disclosures [Line Items]
Tax benefit from reduction in state taxes			$ (12.0)