Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accounts Receivable [Abstract]
Gross accounts receivable pledged as collateral	$ 0	$ 289
Shareholders' equity
Common stock, par value
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares outstanding	856,563,385	855,000,000
Treasury Stock, Shares held	35,000,000	35,000,000
PECO Energy Co [Member]
Accounts Receivable [Abstract]
Gross accounts receivable pledged as collateral		$ 289