Regulatory Matters (Narrative) (Details) (USD $)	12 Months Ended										12 Months Ended											12 Months Ended									12 Months Ended									12 Months Ended														12 Months Ended			3 Months Ended		12 Months Ended								12 Months Ended						12 Months Ended				3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Removal Costs [Member]	Dec. 31, 2011 Removal Costs [Member]	Dec. 31, 2012 Plants Retired [Member]	Dec. 31, 2011 Plants Retired [Member]	Dec. 31, 2012 Other Regulatory Assets [Member]	Dec. 31, 2011 Other Regulatory Assets [Member]	Dec. 31, 2012 Nuclear Deferral [Member]	Dec. 31, 2012 FPSC Settlement Agreement [Member]	Dec. 31, 2012 NCUC Settlement Agreement [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Dec. 31, 2011 Duke Energy Indiana [Member]	Dec. 31, 2010 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Removal Costs [Member]	Dec. 31, 2011 Duke Energy Indiana [Member] Removal Costs [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Plants Retired [Member]	Dec. 31, 2011 Duke Energy Indiana [Member] Plants Retired [Member]	Dec. 31, 2012 Duke Energy Indiana [Member] Other Regulatory Assets [Member]	Dec. 31, 2011 Duke Energy Indiana [Member] Other Regulatory Assets [Member]	Dec. 31, 2014 Duke Energy Ohio [Member]	Dec. 31, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Dec. 31, 2011 Duke Energy Ohio [Member]	Dec. 31, 2010 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Removal Costs [Member]	Dec. 31, 2011 Duke Energy Ohio [Member] Removal Costs [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Other Regulatory Assets [Member]	Dec. 31, 2011 Duke Energy Ohio [Member] Other Regulatory Assets [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Ohio Electric Rate Case [Member]	Dec. 31, 2012 Duke Energy Ohio [Member] Ohio Natural Gas Rate Case [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member]	Dec. 31, 2010 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Removal Costs [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member] Removal Costs [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Other Regulatory Assets [Member]	Dec. 31, 2011 Duke Energy Carolinas [Member] Other Regulatory Assets [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Minimum [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] Maximum [Member]	Dec. 31, 2013 Duke Energy Carolinas [Member] North Carolina Rate Case [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] North Carolina Rate Case [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member] South Carolina Rate Case [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member]	Dec. 31, 2010 Progress Energy Carolinas [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] Removal Costs [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member] Removal Costs [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] Plants Retired [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member] Plants Retired [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] Other Regulatory Assets [Member]	Dec. 31, 2011 Progress Energy Carolinas [Member] Other Regulatory Assets [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] North Carolina Rate Case [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] North Carolina Rate Case [Member] NC Public Staff [Member]	Dec. 31, 2012 Progress Energy Carolinas [Member] North Carolina Rate Case Net Of Energy Efficiency And Demand Side Management [Member]	Sep. 30, 2012 Progress Energy Florida [Member]	Dec. 31, 2011 Progress Energy Florida [Member]	Dec. 31, 2012 Progress Energy Florida [Member]	Dec. 31, 2012 Progress Energy Florida [Member] Removal Costs [Member]	Dec. 31, 2011 Progress Energy Florida [Member] Removal Costs [Member]	Dec. 31, 2012 Progress Energy Florida [Member] Plants Retired [Member]	Dec. 31, 2012 Progress Energy Florida [Member] Other Regulatory Assets [Member]	Dec. 31, 2011 Progress Energy Florida [Member] Other Regulatory Assets [Member]	Dec. 31, 2012 Progress Energy Florida [Member] Nuclear Deferral [Member]	Dec. 31, 2011 Progress Energy Florida [Member] Nuclear Deferral [Member]	Dec. 31, 2012 Progress Energy Florida [Member] FPSC Settlement Agreement [Member]	Dec. 31, 2011 Progress Energy Florida [Member] FPSC Settlement Agreement [Member]	Dec. 31, 2012 Progress Energy Florida [Member] FPSC Settlement Agreement [Member] Minimum [Member]	Dec. 31, 2012 Progress Energy Florida [Member] FPSC Settlement Agreement [Member] Maximum [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member]	Nov. 30, 2009 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] September 7, 2006 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] May 1, 2008 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] November 24, 2009 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] April 16, 2010 [Member]	Sep. 30, 2010 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] September 17, 2010 Settlement Date [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] September 17, 2010 Settlement Date [Member] basispoints	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] March 10, 2011 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] June 27, 2011 [Member]	Sep. 30, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] October 19, 2011 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] October 19, 2011 [Member]	Mar. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] April 30, 2012 Settlement Agreement [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] April 30, 2012 Settlement Agreement [Member]	Sep. 30, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] October 30, 2012 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] October 30, 2012 [Member]	Dec. 31, 2012 Edwardsport Igcc Plant [Member] Duke Energy Indiana [Member] December 27, 2012 [Member]	Dec. 31, 2012 Cliffside Unit6 [Member] Duke Energy Carolinas [Member] MW	Dec. 31, 2012 William State Lee Iii Nuclear Station [Member] Duke Energy Carolinas [Member] MW	Dec. 31, 2012 Regional Transmission Organization Realignment [Member] Duke Energy Ohio [Member]	Dec. 31, 2011 Regional Transmission Organization Realignment [Member] Duke Energy Ohio [Member]	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Removal Costs [Member]	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Plants Retired [Member]	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Nuclear Deferral [Member]	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Planned Scenario [Member] M	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Previous Bid Scenario [Member] M	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Expanded Scope Of Work [Member] M	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Worst Case Scenario [Member] M	Dec. 31, 2012 Crystal River Unit 3 [Member] Progress Energy Florida [Member] Minimum [Member]	Dec. 31, 2012 Levy Nuclear Station [Member] Progress Energy Florida [Member]	Dec. 31, 2012 Levy Nuclear Station [Member] Progress Energy Florida [Member] Minimum [Member]	Dec. 31, 2012 Levy Nuclear Station [Member] Progress Energy Florida [Member] Maximum [Member]	Dec. 31, 2012 Anclote Units 1 and 2 [ Member] Progress Energy Florida [Member]	Dec. 31, 2012 L V Sutton Plant [Member] Progress Energy Carolinas [Member]
Plant capacity, MW																																																																																								825	1,117
Estimated capital cost of new utility plant, excluding AFUDC																																																																																								$ 1,800,000,000
Estimated AFUDC on capital project																																																																										125,000,000		160,000,000												600,000,000
Revised Afudc Financing Costs																																																																																								400,000,000
Estimated capital cost of new utility plant, including AFUDC																																																																																																									600,000,000
Vc Summer Ownership Percentage																																								5.00%	10.00%
Approved rate increase amount by state commission																																											309,000,000	93,000,000
Rate Increase Begin Date																															2013	2013											2/1/2012	2/6/2012										6/1/2013
Return on equity percentage																																										11.25%	10.50%	10.50%										11.25%	10.20%																																			11.38%
Average increase in retail revenues, percentage																															5.10%	6.60%										9.70%	7.20%	5.98%										12.00%		11.00%
Capital structure, equity percentage																																										53.00%	53.00%	53.00%										55.00%	53.00%
Capital structure, long-term debt percentage																																										47.00%	47.00%	47.00%										45.00%
Required shareholder contribution to low income customers or agencies.												5,000,000
Rate Increase, Year One																																																							151,000,000
Average increase in retail revenues, percentage, year one																																																							4.70%
Rate Increase, Year Two																																																							31,000,000
Average increase in retail revenues, percentage, year two																																																							1.00%
Edwardsport IGCC original estimated and approved capital cost, including AFUDC																																																																									1,985,000,000
Edwardsport IGCC revised estimated capital cost, including AFUDC																																																																										2,350,000,000		2,880,000,000		2,760,000,000
Edwardsport IGCC estimated additional capital cost																																																																											150,000,000	530,000,000
Edwardsport IGCC - cost cap for customers																																																																														2,975,000,000						2,595,000,000
Edwardsport IGCC basis point reduction in the equity return for project construction costs																																																																														150
Edwardsport IGCC committed costs, as claimed by intervenors																																																																								1,600,000,000
Impairment charges	666,000,000	335,000,000	726,000,000										579,000,000	234,000,000	44,000,000									2,000,000	89,000,000	837,000,000							31,000,000	12,000,000	0										54,000,000	3,000,000	5,000,000												146,000,000																		44,000,000				222,000,000		400,000,000		180,000,000							192,000,000
Edwardsport IGCC impairment and other charges																																																																																			420,000,000
Edwarsport IGCC original customer rate increase																																																																															19.00%
Edwardsport IGCC revised customer rate increase																																																																															16.00%
Edwardsport IGCC revised estimated capital costs, excluding AFUDC																																																																															2,720,000,000	2,820,000,000		2,980,000,000				3,154,000,000
Edwardsport IGCC legal fee charges from settlement																																																																																			20,000,000
Edwardsport IGCC Customer Credit																																																																																							31,000,000
Edwardsport Damages																																																																							560,000,000
Storm cost deferral													12,000,000
EPA compliance capital costs													395,000,000
Requested rate increase amount to state commission																															87,000,000	45,000,000										446,000,000												387,000,000		359,000,000
Ohio ESP non-bypassable stability charge																						110,000,000	110,000,000	110,000,000
MVP project costs approved by MISO																																																																																											5,200,000,000
MISO exit liability	135,000,000	32,000,000																															12,000,000	1,000,000											23,000,000	5,000,000													6,000,000																															97,000,000	110,000,000
MISO exit recorded to regulatory assets	11,741,000,000	4,046,000,000											936,000,000	912,000,000										625,000,000	548,000,000								1,948,000,000	2,066,000,000											1,922,000,000	1,713,000,000												1,873,000,000	3,500,000,000																																74,000,000
MISO exit fees recorded to expense	171,000,000																																21,000,000												35,000,000														12,000,000																																36,000,000
Repair costs, range of possible costs																																																																																																				900,000,000			1,300,000,000
Replacement power insurance coverage amount, total																																																																																												490,000,000
NEIL coverage per company at each nuclear plant																																																																																												2,250,000,000
Insurance deductible per claim																																																																																												10,000,000
NEIL reimbursements withheld																																																																																												70,000,000
Future Year Four Pro Rata Replacement Power Refund																																																																																												40,000,000
Future year five pro rata replacement power refund																																																																																												60,000,000
Allocated wholesale costs																																																																																																					68,000,000
Property, plant and equipment, additions, proposed																																																																																																						19,000,000,000	24,000,000,000	79,000,000
Public utilities cost of removal reserve reduction taken subject to regulatory order											120,000,000																																																								178,000,000	250,000,000
Public utilities, cost of removal reserve, amount subject to regulatory order																																																																			110,000,000
Future year two customer refunds																																																																			129,000,000
Future year three customer refunds																																																																			129,000,000
Refund to customers recorded as reduction to revenue																																																										(288,000,000)									288,000,000
Future year three residential and small commercial customer refunds																																																																			10,000,000
Future year four residential and small commercial customer refunds																																																																			10,000,000
Future year five residential and small commercial customer refunds																																																																			10,000,000
Public utilities, rate of returns, authorized																																																																						11.50%
Public utilities rate of return authorized																																																																					9.50%
Independent review repair costs																																																																																																1,490,000,000	1,550,000,000	2,440,000,000	3,430,000,000
Independent review, estimated time to return to service																																																																																																35	31	60	96
Replacement power refund																																																									(100,000,000)
Increase in rates total																																																																			150,000,000
NCUC settlement additional fuel cost savings to customers												25,000,000
Additional NEIL insurance proceeds received for Crystal River Unit 3																																																																																												530,000,000
Total NEIL insurance proceeds to be received for Crystal River Unit 3.																																																																																												835,000,000
Total NEIL insurance proceeds received to date for Crystal River Unit 3.																																																																																												305,000,000
Net Investment in Crystal River Unit 3																																																																																												1,637,000,000
Regulatory Assets, Noncurrent	11,004,000,000	3,672,000,000				1,781,000,000	73,000,000	237,000,000	198,000,000	77,000,000			810,000,000	798,000,000				61,000,000	73,000,000	59,000,000	37,000,000			579,000,000	520,000,000				23,000,000	32,000,000			1,727,000,000	1,894,000,000				177,000,000	128,000,000						1,845,000,000	1,682,000,000				128,000,000	15,000,000	35,000,000	41,000,000					1,629,000,000	3,321,000,000			1,592,000,000	21,000,000	39,000,000	77,000,000	129,000,000																												1,592,000,000	25,000,000
Regulatory Liability, Noncurrent	$ 5,584,000,000	$ 2,919,000,000		$ 4,827,000,000	$ 2,586,000,000								$ 741,000,000	$ 683,000,000		$ 624,000,000	$ 590,000,000							$ 254,000,000	$ 273,000,000		$ 236,000,000	$ 230,000,000					$ 2,102,000,000	$ 1,928,000,000		$ 1,928,000,000	$ 1,770,000,000								$ 1,538,000,000	$ 1,543,000,000		$ 1,503,000,000	$ 1,529,000,000									$ 1,024,000,000	$ 787,000,000	$ 401,000,000	$ 550,000,000																																$ 20,000,000