Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Accounts Receivable [Abstract]
Gross accounts receivable pledged as collateral	$ 314,000,000	$ 329,000,000
Unamortized Energy Contracts Assets [Abstract]
Unamortized energy contract assets related to CENG	0	0
Shareholders' equity
Common stock, par value
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	854,283,102	663,000,000
Treasury Stock, Shares held	35,000,000
PECO Energy Co [Member]
Accounts Receivable [Abstract]
Gross accounts receivable pledged as collateral	$ 314,000,000	$ 329,000,000