Commitments And Contingencies (Narrative) (Details) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended		12 Months Ended				60 Months Ended						12 Months Ended
	Sep. 03, 2010	Jun. 30, 2009	Aug. 31, 2011 gal	Jun. 30, 2009	Mar. 31, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2015 Coal Combustion Product Management [Member]	Dec. 31, 2015 Coal Combustion Product Management [Member] Duke Energy Carolinas [Member]	Dec. 31, 2015 Coal Combustion Product Management [Member] Duke Energy Ohio [Member]	Dec. 31, 2015 Coal Combustion Product Management [Member] Duke Energy Indiana [Member]	Dec. 31, 2011 Litigation And Legal Proceedings [Member]	Dec. 31, 2010 Litigation And Legal Proceedings [Member]	Dec. 31, 2011 Federal Advance Clean Coal Tax Credits Associated With Its Construction Of Cliffside Unit6 [Member]	Dec. 31, 2011 Federal Advance Clean Coal Tax Credits Associated With Its Construction Of Edwardsport IGCC Plant [Member]	Dec. 31, 2011 Reserve For Environmental Costs [Member] Duke Energy Ohio [Member]
Remediation reserve						$ 1,208,000,000	$ 1,306,000,000	$ 1,428,000,000	$ 1,632,000,000									$ 28,000,000
Aquatic protection requirements for existing facilities, in gallons			2,000,000
Environmental exit costs, anticipated cost										259,000,000	78,000,000	63,000,000	118,000,000
DEIGP electric transmission charges promulgated by ANEEL		61,000,000
Additional electric transmission fine assessed					9,000,000
Pre-tax charge recorded associated with the resolutions				33,000,000
DEIGP's obligation to expand installed generation capacity, percent						15.00%
Daily penalty faced if DEIGP fails to present a detailed expansion plan						16,000
Alleged amount borrowed from a consortium of banks	1,200,000,000
Probable insurance recoveries						813,000,000	850,000,000
Investment tax credits																125,000,000	134,000,000
Related injuries and damages claims														810,000,000	900,000,000
Deferred Costs																		$ 69,000,000