Common Stock (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Common Stock [Line Items]
Average shares, basic	706	705
Average shares, diluted	706	705
EPS, basic	$ (0.13)	$ 0.89
EPS, diluted	$ (0.13)	$ 0.89
Number of stock options and performance and unvested stock awards excluded from the dilutive securities calculation	2	1
Dividends declared per share	$ 0.78	$ 0.765
Income [Member]
Common Stock [Line Items]
Income from continuing operations attributable to Duke Energy common stockholders, as adjusted for participating securities - basic and diluted	$ (94)	$ 629
Average Shares [Member]
Common Stock [Line Items]
Average shares, basic and diluted	706	705
EPS [Member]
Common Stock [Line Items]
EPS, basic and diluted	$ (0.13)	$ 0.89