Regulatory Matters (Details) (USD $)	0 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended		3 Months Ended			3 Months Ended	0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended			27 Months Ended	36 Months Ended		3 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended				1 Months Ended			1 Months Ended			3 Months Ended				12 Months Ended	3 Months Ended		0 Months Ended
	Dec. 09, 2009	Mar. 31, 2012 entities	Apr. 30, 2007 FERC kv	Mar. 31, 2012 FERC	Jan. 21, 2010 FERC issues	Mar. 31, 2012 FERC PATH kv	Mar. 31, 2012 FERC PJM Calculation Error	Dec. 28, 2011 FERC PJM Calculation Error	Jun. 30, 2011 The Seneca Pumped Storage Project Relicensing	Apr. 22, 2011 OHIO	Aug. 31, 2011 OHIO proposals	Mar. 31, 2012 OHIO Party	Oct. 31, 2009 OHIO proposals	Dec. 31, 2011 OHIO MWh	Dec. 31, 2010 OHIO MWh	Dec. 31, 2009 OHIO MWh	Mar. 31, 2012 OHIO	Dec. 31, 2011 OHIO	Dec. 31, 2010 OHIO	Mar. 31, 2012 MARYLAND	Oct. 06, 2009 MARYLAND	Oct. 31, 2010 PENNSYLVANIA	Mar. 31, 2012 PENNSYLVANIA	Dec. 31, 2010 PENNSYLVANIA	Aug. 29, 2011 PENNSYLVANIA questions	Jun. 30, 2011 PENNSYLVANIA Party	May 31, 2011 PENNSYLVANIA	Feb. 29, 2012 WEST VIRGINIA Facilities	Apr. 30, 2010 WEST VIRGINIA	Jan. 31, 2012 WEST VIRGINIA Facilities	Feb. 29, 2012 WEST VIRGINIA City of New Martinsville entities	Feb. 29, 2012 WEST VIRGINIA Morgantown Energy entities	Oct. 31, 2006 California Claims Matters FERC Proceedings	Mar. 31, 2012 California Claims Matters FERC	Mar. 31, 2012 Yards Creek Pumped Storage Project FERC MW	Mar. 31, 2012 Yards Creek Pumped Storage Project FERC JCP&L	Mar. 31, 2012 The Seneca Pumped Storage Project FERC MW	Dec. 31, 2012 Year 2012 OHIO MWh	Mar. 31, 2012 Year 2013 OHIO MWh	Mar. 31, 2012 Year 2013 PENNSYLVANIA	Apr. 27, 2012 Pending Litigation OHIO
Regulatory Matters [Line Items]
Proposed electric consumption reduction percentage																				10.00%
Proposed electric demand reduction percentage																				15.00%
Expenditures for cost recovery program																					$ 101,000,000
Maximum Amount Of Penalty Assessed Per Day Per Violation																				25,000
Recovery period for expenditures for cost recovery program																					6 years
Load cap percentage minimum												80.00%
Maximum trance award to a single supplier												80.00%
Generation discount for low income customers												6.00%
Costs avoided by customers, integration period												5 years
Costs avoided by customers												360,000,000
Fund to assist low income customers												12,000,000
Legal Parties												19
ESP extension term												2 years
Annual energy savings														410,000	290,000	166,000																						470,000	530,000
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
Reply Period in the Event of Motion Denial																																									20 days
Application for Rehearing, Ruling Period										30 days
Load served from renewable energy resources																	2.00%	1.50%	1.00%
Request for proposals conducted											2		2
Marginal transmission refund period																							29 months
Marginal transmission losses																								254,000,000
Minimum reduction in Utilities reduce energy consumption																											1.00%													3.00%
Minimum reduction in Utilities peak demand																																								4.50%
Target installation smart meter																							25,000
Grace period		30 months																				30 months
Expenditure amortization period																							10 years
Parties Able to Challenge Recovery Amounts																										1
Directed Questions for Investigation																									11
Annualized base rate increase																													40,000,000
Storm restoration deferral period																													5 years
Additional base rate increase																													20,000,000
Decrease in ENEC rates																													20,000,000
Facilities Seeking Certification As Qualified Energy Resource Facilities																														3
Number of electric generation facilities																												3
Number of electric generation facilities, owned by third party																															1	1
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							6,000,000	35,000,000
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
Hydroelectric project																																			400		451
Ownership interest																																				50.00%
Renewal length of operating license																																				40 years
ILP licensure period																																				5 years
Period of cycle									5 years
Regional Enforcement Entities		8
Customer Power Loss Period	P11H