Earnings Per Share and Equity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share And Equity Additional Narrative Information [Abstract]
Stock options not included in the calculation of diluted common shares outstanding									20	14	9
Treasury Stock, Shares held	35				35				35	35	35
Treasury stock, at cost	$ 2,327				$ 2,327				$ 2,327	$ 2,327
Preferred Stock [Line Items]
PECO Cumulative Preferred Securities Redeemable									87
Preferred stock redemption premium									6
Earnings Per Share Diluted
Income from continuing operations
Income from discontinued operations
Net income on common stock									1,719	1,160	2,495
Average common shares outstanding - basic	856	857	856	855	854	854	853	705	856	816	663
Assumed exercise of stock options, performance share awards and restricted stock									4	3	2
Average common shares outstanding - diluted	860	860	860	855	857	857	856	707	860	819	665
Preferred securities					$ 87					$ 87