Commitments and Contingencies (Narrative) (Details) gal in Millions		1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Feb. 02, 2014 T gal	Mar. 31, 2014 USD ($)	Jun. 30, 2015 USD ($) plant Claims project	Jun. 30, 2015 USD ($) plant Claims project	Dec. 31, 2014 USD ($)
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			$ 191,000,000	$ 191,000,000	$ 323,000,000
Charge for agreement in principle			46,000,000	53,000,000
Progress Energy Merger Shareholder Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement Amount				146,000,000
Payments for Legal Settlements				25,000,000
Litigation Settlement Covered by Insurance			121,000,000	$ 121,000,000
Brazil Expansion Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Obligation to expand installed generation capacity, percent				15.00%
Brazil Generation Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Guaranteed Dispatch Level				95.00%
Brazil Generation Issue [Member] | International Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Guaranteed Dispatch Level				100.00%
Ash Basins Fines and Restitution [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense				$ 68,000,000
Ash Basins Community Service and Mitigation [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement, Expense				34,000,000
Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for agreement in principle			71,000,000	81,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			19,000,000	19,000,000	72,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required			250,000,000	250,000,000
Loss Contingency Accrual			$ 18,000,000	18,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Environmental remediation expense					24,000,000
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Minimum [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Coal ash released, in tons | T	30,000
Basin water released, in gallons | gal	24
Duke Energy Carolinas [Member] | North Carolina Ash Basins [Member] | Maximum [Member] | Dan River [Member]
Valuation and Qualifying Accounts [Abstract]
Coal ash released, in tons | T	39,000
Basin water released, in gallons | gal	27
Duke Energy Carolinas [Member] | New Source Review Provisions Of Clean Air Act [Member]
Valuation and Qualifying Accounts [Abstract]
Maximum civil penalties per day for each violation				$ 37,500
Projects with Alleged NSR Violations | project			29	29
Number of Coal Plants with Alleged NSR Violations | plant			25	25
Loss contingency, pending claims, number | Claims			13	13
Remaining Number of Coal Plants with Alleged NSR Violations | plant			13	13
Number of Retired Plants | plant			11	11
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves			$ 564,000,000	$ 564,000,000	575,000,000
Reinsurance retention policy, amount retained				476,000,000
Reinsurance retention policy, excess retention, amount reinsured				864,000,000
Probable insurance recoveries			$ 617,000,000	$ 617,000,000	616,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Non Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims			133	133
Asbestos-related injuries and damages reserves			$ 34,000,000	$ 34,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims			66	66
Asbestos-related injuries and damages reserves			$ 10,000,000	$ 10,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			79,000,000	79,000,000	93,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			22,000,000	22,000,000	37,000,000
Duke Energy Progress [Member] | North Carolina Ash Basins [Member] | USDOJ [Member]
Valuation and Qualifying Accounts [Abstract]
Minimum Master Credit Facility Balance Required			250,000,000	250,000,000
Loss Contingency Accrual			16,000,000	16,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member] | L V Sutton Plant [Member]
Valuation and Qualifying Accounts [Abstract]
Civil Penalty Assessed				25,000,000
Duke Energy Florida [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			36,000,000	36,000,000	$ 36,000,000
Duke Energy Florida [Member] | Westinghouse Electric Company Litigation [Member]
Valuation and Qualifying Accounts [Abstract]
Gain contingency, unrecorded amount			54,000,000	54,000,000
Loss contingency, damages sought, value		$ 510,000,000
Duke Energy Ohio [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			81,000,000	81,000,000
Charge for agreement in principle			46,000,000	53,000,000
Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Estimated Litigation Liability			81,000,000	81,000,000
Charge for agreement in principle			$ 71,000,000	$ 81,000,000