Regulatory Matters (Details) (USD $)	9 Months Ended					12 Months Ended	31 Months Ended		3 Months Ended		9 Months Ended	12 Months Ended					1 Months Ended	9 Months Ended			3 Months Ended		24 Months Ended	9 Months Ended	34 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended		1 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011 2015 WEST VIRGINIA	Sep. 30, 2011 2020 WEST VIRGINIA	Sep. 30, 2011 2025 WEST VIRGINIA	Sep. 30, 2011 MARYLAND	Dec. 31, 2007 MARYLAND	Sep. 30, 2011 MARYLAND	Oct. 06, 2009 MARYLAND	Sep. 30, 2011 OHIO legal_parties	Oct. 31, 2009 OHIO proposals	Sep. 30, 2011 OHIO	Dec. 31, 2013 OHIO mW	Dec. 31, 2012 OHIO mW	Dec. 31, 2011 OHIO mW	Dec. 31, 2010 OHIO mW	Dec. 31, 2009 OHIO mW	Oct. 31, 2010 PENNSYLVANIA	Sep. 30, 2011 PENNSYLVANIA	May 31, 2013 PENNSYLVANIA	May 31, 2011 PENNSYLVANIA	Sep. 30, 2011 Allegheny WEST VIRGINIA	Sep. 30, 2011 WEST VIRGINIA	Sep. 30, 2011 WEST VIRGINIA	Sep. 30, 2011 WEST VIRGINIA FERC	Dec. 31, 2010 WEST VIRGINIA FERC	Sep. 30, 2011 California Claims Matters	Jun. 30, 2011 The Seneca Pumped Storage Project Relicensing	Sep. 30, 2011 The Seneca Pumped Storage Project FERC mW	Apr. 30, 2007 FERC kv	Sep. 30, 2011 FERC	Jan. 21, 2010 FERC issues	Nov. 30, 2010 FERC PATH	Sep. 30, 2011 FERC PATH kv	Sep. 30, 2011 Penelec	Sep. 30, 2011 Met-Ed	Sep. 30, 2011 Met-Ed	Aug. 23, 2010 Met-Ed
Regulatory Matters [Line Items]
Costs Avoided By Customers											$ 360,000,000
Fund To Assist Low Income Customers											12,000,000
Utilities Required To Additionally Reduce Peak Demand											0.75%
Load Served From Renewable Energy Resources															0.50%	0.25%
Request For Proposals Conducted										2
Number of legal parties									1								1
Annual Energy Savings												530,000	470,000	410,000	290,000	166,000
Utilities Required To Reduce Peak Demand																1.00%
Description of vegetation encroachment event																																					230
Settlement Penalty																																			650,000
Proposed electric consumption reduction percentage					10.00%
Proposed electric demand reduction percentage					15.00%
Expenditures for cost recovery program								101,000,000
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%
Marginal transmission losses																		254,000,000																65,000,000		189,000,000
Minimum reduction in Utilities reduce energy consumption																			3.00%	1.00%
Minimum reduction in Utilities peak demand																			4.50%
Assessment period costs																		29,500,000
Smart meter infrastructure deployed																		725,000
Target installation smart meter																		25,000
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
Number of settlements for which liability charges are fix																														9
Number of settlements for which relevant payment has been made																														8
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
Settlement proposal claims																										190,000,000
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
New Voltage transmission facilities across PJM and a zonal transmission rate (In KV)																																	765
Duration of Plan Approved As Per Order																3 years
Period of the portfolio plans filed seeking approval for the program																3 years
Period of Cycle						5 years																					5 years
Recovery Period For Expenditures For Cost Recovery Program								6 years
Hydroelectric project																												451
Assessment period	24 months
Grace period	30 months																30 months
Extension of comment period	30 days