Acquisitions and Sales of Other Assets (Purchase Price Calculation) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended
	Jul. 02, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Acquisitions and Disposals [Line Items]
Progress Energy common shares outstanding		706,000,000	704,000,000	445,000,000	443,000,000
Exchange ratio	87.083%
Duke Energy common shares issued for Progress Energy common shares outstanding	257,867,000
Closing price of Duke Energy common shares	$ 69.84
Purchase price for common shares	$ 18,009
Fair value of outstanding earned stock compensation awards	62
Total estimated purchase price	$ 18,071
Progress Energy [Member]
Significant Acquisitions and Disposals [Line Items]
Progress Energy common shares outstanding	296,116,000	100	100