Regulatory Matters (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended				9 Months Ended			9 Months Ended		9 Months Ended							3 Months Ended		9 Months Ended				9 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended			9 Months Ended	3 Months Ended		9 Months Ended									9 Months Ended				9 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended				9 Months Ended	36 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2012 Duke Energy Carolinas [Member]	Sep. 30, 2012 Duke Energy Carolinas [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member]	Dec. 31, 2012 Duke Energy Carolinas [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Retired Generation Facilities [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case [Member] NCUC [Member] Removal Costs Reduction Year One [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case [Member] NCUC [Member] Removal Costs Reduction Year Two [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case [Member] PSCSC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case [Member] PSCSC [Member] Removal Costs Reduction [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case Step One [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case Step One [Member] PSCSC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case Step Two [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] Rate Case Step Two [Member] PSCSC [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] V.C. Summer Nuclear Station [Member] Minimum [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] V.C. Summer Nuclear Station [Member] Maximum [Member]	Sep. 30, 2013 Duke Energy Carolinas [Member] William State Lee III Nuclear Station [Member]	Sep. 30, 2013 Duke Energy Progress [Member]	Sep. 30, 2012 Duke Energy Progress [Member]	Sep. 30, 2013 Duke Energy Progress [Member]	Sep. 30, 2012 Duke Energy Progress [Member]	Dec. 31, 2012 Duke Energy Progress [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Retired Generation Facilities [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Rate Case [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Rate Case [Member] NCUC [Member] Removal Costs Reduction [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Rate Case Step One [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Rate Case Step Two [Member] NCUC [Member]	Sep. 30, 2013 Duke Energy Progress [Member] L V Sutton Plant [Member]	Sep. 30, 2013 Duke Energy Progress [Member] Shearon Harris Nuclear Station [Member]	Sep. 30, 2013 Duke Energy Florida [Member]	Sep. 30, 2012 Duke Energy Florida [Member]	Sep. 30, 2013 Duke Energy Florida [Member]	Sep. 30, 2012 Duke Energy Florida [Member]	Dec. 31, 2012 Duke Energy Florida [Member]	Sep. 30, 2013 Duke Energy Florida [Member] 2012 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2012 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2012 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member] Minimum [Member]	Sep. 30, 2013 Duke Energy Florida [Member] 2013 FPSC Settlement Agreement [Member] Maximum [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] Amount Subject To Cost Cap [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] Uprate And Dry Cask Storage Projects [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] Minimum [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] Maximum [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] 2012 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Crystal River Unit 3 [Member] NEIL Settlement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Levy Nuclear Station [Member]	Sep. 30, 2013 Duke Energy Florida [Member] Levy Nuclear Station [Member] 2013 FPSC Settlement Agreement [Member]	Sep. 30, 2013 Duke Energy Florida [Member] New Generation Needs [Member] 2013 FPSC Settlement Agreement [Member] MW	Sep. 30, 2013 Duke Energy Ohio [Member]	Dec. 31, 2012 Duke Energy Ohio [Member]	Sep. 30, 2013 Duke Energy Ohio [Member] Electric Rate Case [Member] PUCO [Member]	Sep. 30, 2013 Duke Energy Ohio [Member] Natural Gas Rate Case [Member] PUCO [Member]	Sep. 30, 2013 Duke Energy Ohio [Member] Capacity Rider Filing [Member]	Sep. 30, 2013 Duke Energy Ohio [Member] RTO Realignment [Member]	Sep. 30, 2013 Duke Energy Indiana [Member]	Sep. 30, 2012 Duke Energy Indiana [Member]	Sep. 30, 2013 Duke Energy Indiana [Member]	Sep. 30, 2012 Duke Energy Indiana [Member]	Dec. 31, 2012 Duke Energy Indiana [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Retired Generation Facilities [Member]	Sep. 30, 2012 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event April 16, 2010 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event June 27, 2011 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event October 19, 2011 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event October 30, 2012 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event November 20, 2007 [Member]	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event January 2009	Sep. 30, 2013 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member] Edwardsport Event December 27, 2012
Public Utilities, General Disclosures [Line Items]
Combined cycle capacity, MW																																																									1,150
Additional generation capacity, MW																																																									1,800
Estimated AFUDC on capital project																																																																								$ 160,000,000					$ 125,000,000
Estimated capital cost of new utility plant, including AFUDC																																	570,000,000
Percentage of completion of construction																																	94.00%
Net property, plant and equipment	69,284,000,000		69,284,000,000		68,558,000,000			23,185,000,000	22,826,000,000													370,000,000	13,442,000,000		13,442,000,000		13,062,000,000								9,514,000,000		9,514,000,000		9,360,000,000																117,000,000			8,191,000,000	8,126,000,000					8,471,000,000		8,471,000,000		8,320,000,000
VC summer ownership percentage																				5.00%	10.00%
Approved rate increase amount by state commission																205,000,000	80,000,000	30,000,000	38,000,000												147,000,000	31,000,000								150,000,000																				49,000,000
Requested rate increase amount to state commission																																																													63,000,000
Rate increase begin date											9/25/2013			9/18/2013															6/1/2013																															5/1/2013
Approved rate increase percentage by state commission																4.50%	5.50%	0.60%	2.60%												4.50%	1.00%																												2.90%
Approved return on equity percentage amount by state commission											10.20%			10.20%															10.20%																9.50%	11.50%							7.35%				10.50%			9.84%	9.84%
Approved equity capital structure, percentage											53.00%			53.00%															53.00%
Required shareholder contribution to low income customers or agencies.											10,000,000			4,000,000															20,000,000
Impairment charges	2,000,000	266,000,000	388,000,000	668,000,000		31,000,000	31,000,000																0	55,000,000	22,000,000	55,000,000								22,000,000	1,000,000	0	346,000,000	0															295,000,000			65,000,000								0	180,000,000	0	580,000,000			600,000,000	897,000,000
Edwardsport IGCC original estimated and approved capital cost, including AFUDC																																																																												1,985,000,000
Edwardsport IGCC revised estimated capital cost, including AFUDC																																																																								2,880,000,000					2,350,000,000
Cost Cap for customers																																																					1,466,000,000																									2,595,000,000
Edwardsport IGCC revised estimated capital costs, excluding AFUDC																																																																									2,820,000,000	2,980,000,000	3,150,000,000
EPA compliance capital costs																																																																		395,000,000
Capacity rider revenues requested																																																														729,000,000
MVP project costs approved by MISO																																																															5,500,000,000
Future revenue requirement discount rate																																																															8.20%
MVP projects future revenue requirements obligation																																																															514,000,000
Recovery costs not sought																																																															121,000,000
Repair costs, range of possible costs																																																		900,000,000	1,300,000,000
Net unrecovered investment																																																								265,000,000
Public utilities, cost of removal reserve, reduction taken subject to regulatory order																																									22,000,000	60,000,000	95,000,000	118,000,000
Public utilities, cost of removal reserve, amount subject to regulatory order																																									19,000,000		19,000,000
Refund to customers recorded as reduction to revenue																																								288,000,000												100,000,000
Independent review repair costs																																																		1,490,000,000	3,430,000,000
Decommissioning cost study estimate																																															989,000,000
Total insurance proceeds received to date																																																						835,000,000
Current year insurance proceeds received to date																																																						530,000,000
Future customer credit																																																								10,000,000
Acceleration of cash recovery through fuel clause																																																					135,000,000
Decommissioning trust funding																																											8,000,000
Regulatory assets, noncurrent	10,220,000,000		10,220,000,000		11,004,000,000			1,794,000,000	1,727,000,000	71,000,000													1,558,000,000		1,558,000,000		1,845,000,000	187,000,000						47,000,000	3,007,000,000		3,007,000,000		3,321,000,000									1,186,000,000,000	324,000,000						118,000,000			556,000,000	579,000,000				70,000,000	790,000,000		790,000,000		810,000,000	57,000,000
Regulatory liability, noncurrent	5,904,000,000		5,904,000,000		5,584,000,000			2,484,000,000	2,102,000,000			30,000,000	30,000,000		45,000,000								1,743,000,000		1,743,000,000		1,538,000,000			20,000,000					640,000,000		640,000,000		787,000,000															490,000,000				257,000,000	254,000,000					766,000,000		766,000,000		741,000,000
Other current assets																																																							$ 30,000,000