Commitments and Contingencies (Narrative) (Details)		1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 02, 2014 gal T	Mar. 31, 2014 USD ($)	Sep. 30, 2015 USD ($) plant Claims project	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) plant Claims project	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Aug. 18, 2014 gal
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			$ 178,000,000		$ 178,000,000		$ 323,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			1,426,000,000	$ 1,409,000,000	4,274,000,000	$ 4,254,000,000
Investments and other assets			3,205,000,000		3,205,000,000		3,008,000,000
Accounts Payable, Current			2,078,000,000		2,078,000,000		2,271,000,000
Charge for settlement agreement					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%
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 settlement agreement					81,000,000
Duke Energy Carolinas [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			12,000,000		12,000,000		72,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			511,000,000	465,000,000	1,469,000,000	1,415,000,000
Investments and other assets			1,018,000,000		1,018,000,000		959,000,000
Accounts Payable, Current			623,000,000		623,000,000		709,000,000
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			$ 5,000,000		5,000,000
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	24,000,000
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	27,000,000
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
Gain (Loss) Related to Litigation Settlement					$ 4,000,000
Litigation Settlement, Expense					1,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			$ 2,000,000		2,000,000
Investments and other assets			3,000,000		3,000,000
Accounts Payable, Current			5,000,000		5,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member]
Valuation and Qualifying Accounts [Abstract]
Asbestos-related injuries and damages reserves			551,000,000		551,000,000		575,000,000
Reinsurance retention policy, excess retention, amount reinsured					847,000,000
Probable insurance recoveries			$ 599,000,000		$ 599,000,000		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			150		150
Asbestos-related injuries and damages reserves			$ 37,000,000		$ 37,000,000
Duke Energy Carolinas [Member] | Asbestos Issue [Member] | Malignant Asbestos Claim [Member]
Valuation and Qualifying Accounts [Abstract]
Loss contingency, pending claims, number | Claims			63		63
Asbestos-related injuries and damages reserves			$ 9,000,000		$ 9,000,000
Duke Energy Carolinas [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement					1,000,000
Progress Energy [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			74,000,000		74,000,000		93,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			539,000,000	564,000,000	1,672,000,000	1,714,000,000
Investments and other assets			850,000,000		850,000,000		670,000,000
Accounts Payable, Current			697,000,000		697,000,000		847,000,000
Duke Energy Progress [Member]
Valuation and Qualifying Accounts [Abstract]
Loss Contingency Accrual			17,000,000		17,000,000		37,000,000
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			329,000,000	346,000,000	1,066,000,000	1,074,000,000
Investments and other assets			484,000,000		484,000,000		412,000,000
Accounts Payable, Current			381,000,000		381,000,000		481,000,000
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			5,000,000		5,000,000
Duke Energy Progress [Member] | Groundwater Violation [Member]
Valuation and Qualifying Accounts [Abstract]
Charge for settlement agreement					6,000,000
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
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			208,000,000	212,000,000	598,000,000	626,000,000
Investments and other assets			308,000,000		308,000,000		204,000,000
Accounts Payable, Current			316,000,000		316,000,000		365,000,000
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
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			124,000,000	134,000,000	370,000,000	378,000,000
Investments and other assets			17,000,000		17,000,000		23,000,000
Accounts Payable, Current			219,000,000		219,000,000		209,000,000
Charge for settlement agreement					53,000,000
Duke Energy Ohio [Member] | W.C. Beckjord Station [Member]
Valuation and Qualifying Accounts [Abstract]
Gallons of Fuel Released | gal								9,000
Duke Energy Ohio [Member] | Antitrust Lawsuit [Member]
Valuation and Qualifying Accounts [Abstract]
Litigation Settlement Amount					81,000,000
Charge for settlement agreement					81,000,000
Duke Energy Indiana [Member]
Valuation and Qualifying Accounts [Abstract]
Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses			164,000,000	$ 160,000,000	525,000,000	$ 485,000,000
Accounts Payable, Current			$ 149,000,000		$ 149,000,000		$ 179,000,000