Risk Management, Derivative Instruments And Hedging Activities (Undesignated Contracts - Location And Amount Of Pre-Tax Gains And (Losses) Recognized In Income Or As Regulatory Assets Or Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
Total Pre-tax Gains (Losses) Recognized as Regulatory Assets or Liabilities	$ (209)		$ 78
Total Pre-tax Losses Recognized in Earnings	(60)		(28)
Revenue, Regulated Electric [Member]
Total Pre-tax Losses Recognized in Earnings			1
Revenue, Non-Regulated Electric, Natural Gas And Other [Member]
Total Pre-tax Losses Recognized in Earnings	(59)		(38)
Fuel Used In Electric Generation And Purchased Power-Non-Regulated [Member]
Total Pre-tax Losses Recognized in Earnings	(1)		9
Regulatory Asset [Member] | Interest Rate Contracts [Member]
Regulatory Asset	(165)	[1]	(1)	[1]
Regulatory Asset [Member] | Commodity Contracts [Member]
Regulatory Asset	(1)		5
Regulatory Liability [Member] | Interest Rate Contracts [Member]
Regulatory Liability	(60)	[2]	60	[2]
Regulatory Liability [Member] | Commodity Contracts [Member]
Regulatory Liability	$ 17		$ 14

[1] Includes losses related to interest rate swaps at Duke Energy Carolinas and Duke Energy Indiana of $94 million and $67 million, respectively, during the year ended December 31, 2011.

[2] Amounts relate to interest rate swaps at Duke Energy Carolinas.