Consolidated Balance Sheets (Jersey Central Power & Light Company) (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Common stockholders' equity-
Common stock, par value (in dollars per share)	$ 0.1	$ 0.1
Common stock, shares authorized	490,000,000	490,000,000
Common stock, shares outstanding	418,216,437	418,216,437
Customer [Member]
Receivables-
Allowance for uncollectible accounts	$ 40	$ 37
JCP&L
Common stockholders' equity-
Common stock, par value (in dollars per share)	$ 10	$ 10
Common stock, shares authorized	16,000,000	16,000,000
Common stock, shares outstanding	13,628,447	13,628,447
JCP&L | Customer [Member]
Receivables-
Allowance for uncollectible accounts	$ 3	$ 3