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	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Total Pre-tax Gains (Losses) Recognized as Regulatory Assets or Liabilities	$ 26		$ 11
Total Pre-tax Losses Recognized in Earnings	36	[1]	(14)	[1]
Revenue, Non-Regulated Electric, Natural Gas And Other [Member]
Total Pre-tax Losses Recognized in Earnings	36		(13)
Fuel Used In Electric Generation And Purchased Power-Non-Regulated [Member]
Total Pre-tax Losses Recognized in Earnings			(1)
Regulatory Asset [Member] | Interest Rate Contracts [Member]
Regulatory Asset	22
Regulatory Asset [Member] | Commodity Contracts [Member]
Regulatory Asset	(1)
Regulatory Liability [Member] | Interest Rate Contracts [Member]
Regulatory Liability			12
Regulatory Liability [Member] | Commodity Contracts [Member]
Regulatory Liability	$ 5		$ (1)

[1] Amounts include Duke Energy Ohio intercompany positions that are eliminated at Duke Energy.