Regulatory Matters (Details) (USD $)	12 Months Ended				1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended			12 Months Ended		31 Months Ended		3 Months Ended	12 Months Ended					24 Months Ended	36 Months Ended		1 Months Ended	12 Months Ended			12 Months Ended	24 Months Ended	12 Months Ended		34 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011 Penelec	Dec. 31, 2011 Met-Ed	Aug. 23, 2010 Met-Ed kv	Apr. 30, 2007 FERC kv	Dec. 31, 2011 FERC	Jan. 21, 2010 FERC issues	Nov. 30, 2010 FERC PATH	Dec. 31, 2011 FERC PATH kv	Dec. 31, 2011 PJM Calculation Error	Dec. 28, 2011 PJM Calculation Error	Dec. 31, 2011 MARYLAND	Dec. 31, 2007 MARYLAND	Sep. 30, 2011 MARYLAND	Oct. 06, 2009 MARYLAND	Oct. 31, 2009 OHIO proposals	Dec. 31, 2013 OHIO MWh	Dec. 31, 2012 OHIO MWh	Dec. 31, 2011 OHIO legal_parties MWh	Dec. 31, 2010 OHIO MWh	Dec. 31, 2009 OHIO MWh	Dec. 31, 2011 OHIO	Dec. 31, 2011 OHIO	Dec. 31, 2010 OHIO	Oct. 31, 2010 PENNSYLVANIA Party	Dec. 31, 2011 PENNSYLVANIA	May 31, 2013 PENNSYLVANIA	May 31, 2011 PENNSYLVANIA	Dec. 31, 2011 WEST VIRGINIA	Sep. 30, 2011 WEST VIRGINIA	Dec. 31, 2011 WEST VIRGINIA Allegheny	Dec. 31, 2011 WEST VIRGINIA FERC	Dec. 31, 2010 WEST VIRGINIA FERC	Dec. 31, 2011 Yards Creek Pumped Storage Project [Member] FERC MW	Dec. 31, 2011 Yards Creek Pumped Storage Project [Member] FERC JCP&L	Oct. 31, 2006 California Claims Matters Proceedings	Dec. 31, 2011 California Claims Matters	Jun. 30, 2011 The Seneca Pumped Storage Project Relicensing	Dec. 31, 2011 The Seneca Pumped Storage Project FERC MW	Dec. 31, 2011 2015 WEST VIRGINIA	Dec. 31, 2011 2020 WEST VIRGINIA	Dec. 31, 2011 2025 WEST VIRGINIA
Regulatory Matters [Line Items]
Description of vegetation encroachment event				230
Settlement Penalty			$ 650,000
Cycle length													5 years																									5 years
Proposed electric consumption reduction percentage												10.00%
Proposed electric demand reduction percentage												15.00%
Expenditures for cost recovery program															101,000,000
Recovery Period For Expenditures For Cost Recovery Program															6 years
Termination Moritoria, Statutory														1 day
Termination Moratoria, Proposed														3 days
Maximum amount of penalty assessed per day per violation												25,000
Load Cap Percentage Minimum																			80.00%
Generation Discount For Low Income Customers																			6.00%
Costs Avoided By Customers																			360,000,000
Fund To Assist Low Income Customers																			12,000,000
Annual Energy Savings																	530,000	470,000	410,000	290,000	166,000
Utilities Required To Reduce Peak Demand																					1.00%
Utilities Required To Additionally Reduce Peak Demand																			0.75%
Period of the portfolio plans filed seeking approval for the program																					3 years
Duration of Plan Approved As Per Order																					3 years
Load Served From Renewable Energy Resources																						2.00%	1.50%	1.00%
Request For Proposals Conducted																2
Number of legal parties																			1						1
Marginal transmission losses		65,000,000	189,000,000																							254,000,000
Minimum reduction in Utilities reduce energy consumption																											3.00%	1.00%
Minimum reduction in Utilities peak demand																											4.50%
Target installation smart meter																										25,000
Grace period	30 months																								30 months
Extension of comment period	30 days
Specified minimum percentage of electricity sold to retail customers																																								10.00%	15.00%	25.00%
Purchased Power Cost Recovery																													32,000,000
Increase in fuel and purchased power costs																														3.00%
Synergy Savings																															2,500,000
Actual Purchased Power Cost Recovery from Approved Settlement																													19,600,000
Power Threshold For Cost Methodology					500
Identified Issues For Written Comments							9
One time payment, ATSI agreed to MISO						1,800,000
Annual Revenue requirements in Zone						15,000,000
Losses Incurred Due to Underfunding of Contracts											35,000,000
Projected Losses Due To Underfunding of Contracts										6,000,000
Settlement proposal claims																																					190,000,000
Court Proceedings from Filed Claims																																				1
New Voltage transmission facilities across PJM and a zonal transmission rate (In KV)									765
Return on equity granted as incentive rider								1.50%
Return on equity granted for RTO participation								0.50%
Base ROE																																10.40%	10.80%
Portion of refund due to FirstEnergy																																	$ 2,000,000
Hydroelectric project																																		400					451
Undivided interest																																			50.00%
ILP Licensure Period																																			2 years