Earnings Per Share

3 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]

Earnings Per Share

12. Earnings Per Common Share (EPS)

Basic Earnings Per Share (EPS) is computed by dividing net income attributable to Duke Energy common shareholders, adjusted for distributed and undistributed earnings allocated to participating securities, by the weighted-average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income attributable to Duke Energy common shareholders, as adjusted for distributed and undistributed earnings allocated to participating securities, by the diluted weighted-average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options, phantom shares and stock-based performance unit awards were exercised or settled.

The following table illustrates Duke Energy's basic and diluted EPS calculations and reconciles the weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three months ended March 31, 2012 and 2011.

	Income		Average Shares		EPS
	(in millions, except per- share amounts)
Three Months Ended March 31, 2012
Income from continuing operations attributable to Duke Energy common shareholders, as adjusted for participating securities—basic and diluted	$	292		1,337	$	0.22
Three Months Ended March 31, 2011
Income from continuing operations attributable to Duke Energy common shareholders, as adjusted for participating securities—basic	$	510		1,330	$	0.38
Effect of dilutive securities:
Stock options, performance and restricted stock				1
Income from continuing operations attributable to Duke Energy common shareholders, as adjusted for participating securities—diluted	$	510		1,331	$	0.38

As of March 31, 2012 and 2011, 4 million and 13 million, respectively, of stock options and performance and unvested stock awards were not included in the "effect of dilutive securities" in the above table because either the option exercise prices were greater than the average market price of the common shares during those periods, or performance measures related to the awards had not yet been met