Consolidated Statements of Common Stockholders' Equity (Jersey Central Power & Light Company) (USD $) In Millions, except Share data	Total	Common Stock	Other Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	JCP&L	JCP&L Common Stock	JCP&L Other Paid-In Capital	JCP&L Accumulated Other Comprehensive Income (Loss)	JCP&L Retained Earnings (Accumulated Deficit)
Beginning Balance at Dec. 31, 2009		$ 31	$ 5,448	$ 527	$ 3,012		$ 136	$ 2,507	$ 58	$ (41)
Beginning Balance, Shares at Dec. 31, 2009		304,835,407					13,628,447
NET INCOME	718					183				183
Pension and other postretirement benefits, net of income taxes				(129)					(7)
Cash dividends declared on common stock					(670)					(165)
Consolidated tax benefit allocation								2
Ending Balance at Dec. 31, 2010		31	5,444	425	3,084		136	2,509	51	(23)
Ending Balance, Shares at Dec. 31, 2010		304,835,407					13,628,447
NET INCOME	47					23
Ending Balance at Mar. 31, 2011
Beginning Balance at Dec. 31, 2010		31	5,444	425	3,084		136	2,509	51	(23)
Beginning Balance, Shares at Dec. 31, 2010		304,835,407					13,628,447
NET INCOME	869					144				144
Pension and other postretirement benefits, net of income taxes				(26)					(12)
Cash dividends declared on common stock					(922)
Cash dividends as return of capital								(500)
Consolidated tax benefit allocation								2
Ending Balance at Dec. 31, 2011	13,280	42	9,765	426	3,047	2,307	136	2,011	39	121
Ending Balance, Shares at Dec. 31, 2011	418,216,437	418,216,437				13,628,447	13,628,447
Beginning Balance at Sep. 30, 2011
NET INCOME	99					(9)
Ending Balance at Dec. 31, 2011	13,280	42	9,765			2,307	136
Ending Balance, Shares at Dec. 31, 2011	418,216,437	418,216,437				13,628,447	13,628,447
NET INCOME	306					26
Ending Balance at Mar. 31, 2012
Beginning Balance at Dec. 31, 2011	13,280	42	9,765	426	3,047	2,307	136		39	121
Beginning Balance, Shares at Dec. 31, 2011	418,216,437	418,216,437				13,628,447	13,628,447
NET INCOME	771					133				133
Pension and other postretirement benefits, net of income taxes				(39)					(7)
Cash dividends declared on common stock					(920)					(190)
Ending Balance at Dec. 31, 2012	13,084	42	9,769	385	2,888	2,243	136	2,011	32	64
Ending Balance, Shares at Dec. 31, 2012	418,216,437	418,216,437				13,628,447	13,628,447
Beginning Balance at Sep. 30, 2012
NET INCOME	(148)					(9)
Ending Balance at Dec. 31, 2012	$ 13,084	$ 42	$ 9,769			$ 2,243	$ 136	$ 2,011
Ending Balance, Shares at Dec. 31, 2012	418,216,437	418,216,437				13,628,447	13,628,447