Commitments And Contingencies (Narrative) (Details) (USD $)					9 Months Ended				9 Months Ended				9 Months Ended						12 Months Ended	9 Months Ended
	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2012 Duke Energy Carolinas [Member]		Dec. 31, 2011 Duke Energy Carolinas [Member]		Sep. 30, 2012 Duke Energy Indiana [Member]		Dec. 31, 2011 Duke Energy Indiana [Member]		Sep. 30, 2012 Paranapanema Lawsuit [Member]	Sep. 30, 2012 Brazil Expansion Lawsuit [Member]	Sep. 30, 2012 Crescent Litigation [Member]	Sep. 30, 2012 Asbestos Issue [Member] Duke Energy Carolinas [Member] Claims	Dec. 31, 2011 Asbestos Issue [Member] Duke Energy Carolinas [Member]	Sep. 30, 2012 Spent Nuclear Fuels [Member]	Dec. 31, 2009 Synthetic Fuels [Member]	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Minimum [Member] Alaskan Global Warming Lawsuit [Member]	Sep. 30, 2012 Maximum [Member]	Sep. 30, 2012 Maximum [Member] Alaskan Global Warming Lawsuit [Member]
Estimated cost of complying with recently issued and proposed EPA regulations																				$ 6,000,000,000		$ 7,000,000,000
Amount of claim(s)															1,200,000,000						95,000,000		400,000,000
Additional assessment under resolutions promulgated by ANEEL													60,000,000
Fines imposed by ANEEL due to DEIGP's refusal to pay additional assessments													10,000,000
Pre-tax charge recorded													33,000,000
Obligation to expand installed generation capacity, percent														15.00%
Federal Clean Coal Tax Credits					125,000,000				134,000,000
Number of nonmalignant asbestos related claims																132
Cumulative relief sought for nonmalignant asbestos related claims																33,000,000
Number of malignant asbestos related claims																47
Cumulative relief sought for malignant asbestos related claims																16,000,000
Asbestos-related injuries and damages reserves																763,000,000	801,000,000
Asbestos related injuries and damages self insured retention																476,000,000
Policy limit for potential future insurance recoveries for indemnification and medical cost claim payments in excess of self insured limit																935,000,000
Probable insurance recoveries	781,000,000	[1],[2]	813,000,000	[1],[2]	781,000,000	[1],[2]	813,000,000	[1],[2]								(781,000,000)	(813,000,000)
Reserves for legal matters	975,000,000	[3],[4]	810,000,000	[3],[4]	763,000,000	[3],[4]	801,000,000	[3],[4]	7,000,000	[3]	4,000,000	[3]
Gain Contingency Asserted Damage																		113,000,000
Judgment Award																			78,000,000
Prejudgment interest																			55,000,000
Total Judgment																			133,000,000
Judgment payment																			$ 154,000,000

[1] Insurance recoveries are classified in the respective Condensed Consolidated Balance Sheets in Other within Investments and Other Assets and Receivables.

[2] Relates to recoveries associated with aforementioned asbestos-related injuries and damages claims.

[3] Reserves are classified in the respective Condensed Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Other within Current Liabilities.

[4] Includes reserves for aforementioned asbestos-related injuries and damages claims.