Regulatory Matters (Details) (USD $)	0 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended			9 Months Ended	0 Months Ended	9 Months Ended		0 Months Ended								9 Months Ended			1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended	30 Months Ended	36 Months Ended		9 Months Ended						12 Months Ended						1 Months Ended	9 Months Ended		1 Months Ended		12 Months Ended	1 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Dec. 09, 2008	Sep. 30, 2012 entities	Apr. 30, 2007 FERC kv	Sep. 30, 2012 FERC class	Jan. 21, 2010 FERC issues	Sep. 30, 2012 FERC PJM	Sep. 30, 2012 FERC PJM FTR Allocation Complaint	Aug. 24, 2012 FERC PATH	Sep. 30, 2012 FERC PATH kv	Sep. 20, 2012 FERC PATH	Aug. 24, 2012 FERC PATH-Allegheny	Aug. 24, 2012 FERC Path-WV	Dec. 28, 2011 FERC PJM Calculation Error	Dec. 28, 2011 FERC PJM Calculation Error FES	Dec. 28, 2011 FERC PJM Calculation Error AE Supply	Sep. 30, 2012 Delivery Year 2011-2012 FERC PJM Calculation Error	Sep. 30, 2012 Delivery Year 2011-2012 FERC PJM Calculation Error FES	Sep. 30, 2012 Delivery Year 2011-2012 FERC PJM Calculation Error AE Supply	Sep. 30, 2012 MARYLAND	Aug. 31, 2011 MARYLAND	Oct. 06, 2009 MARYLAND	Aug. 31, 2011 OHIO proposals	Oct. 31, 2009 OHIO proposals	Sep. 30, 2012 OHIO plan	Dec. 31, 2009 OHIO	Jun. 30, 2012 OHIO	Dec. 31, 2011 OHIO	Dec. 31, 2010 OHIO	Sep. 30, 2012 OHIO Year 2012 GWh MWh	Sep. 30, 2012 OHIO Year 2013 GWh	Sep. 30, 2012 OHIO Year 2014 GWh	Sep. 30, 2012 OHIO Annually Through 2025 GWh	Sep. 30, 2012 OHIO Annually Through 2018	Sep. 30, 2012 PENNSYLVANIA smart_meter	Dec. 31, 2010 PENNSYLVANIA	Sep. 30, 2011 PENNSYLVANIA Party	May 31, 2011 PENNSYLVANIA	Apr. 29, 2011 PENNSYLVANIA questions	Sep. 30, 2012 PENNSYLVANIA Statutory Penalty	Sep. 30, 2012 PENNSYLVANIA Year 2013	Apr. 30, 2010 WEST VIRGINIA	Sep. 30, 2012 WEST VIRGINIA MW	Feb. 28, 2011 WEST VIRGINIA Facilities	Feb. 28, 2011 WEST VIRGINIA City of New Martinsville entities	Feb. 28, 2011 WEST VIRGINIA Morgantown Energy entities	Dec. 31, 2013 WEST VIRGINIA Forecast	Oct. 31, 2006 California Claims Matters FERC Proceedings	Sep. 30, 2012 California Claims Matters FERC	Sep. 30, 2012 Yards Creek Pumped Storage Project FERC MW	Sep. 30, 2012 Yards Creek Pumped Storage Project FERC JCP&L	Sep. 30, 2012 The Seneca Pumped Storage Project FERC MW	Sep. 30, 2012 The Seneca Pumped Storage Project Relicensing
Regulatory Matters [Line Items]
Proposed electric consumption reduction percentage																			10.00%
Proposed electric demand reduction percentage																			15.00%
Expenditures for cost recovery program																				$ 66,000,000	$ 101,000,000
Recovery period for expenditures for cost recovery program																				3 years	6 years
Maximum penalty assessed, in dollars per day per violation																			25,000
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
ESP extension term																								2 years
Generation supply auction period, after approval																								3 years
Generation supply auction period, before approval																								1 year
Annual energy savings																													1,211	1,726	2,306	2,903
Increase (decrease) in annual energy savings																													416,000
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
Number of plans																								3
Portfolio plan, estimated cost																								250,000,000
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%
Loss contingency, maximum																																							20,000,000
Target installation smart meter																																		25,000
Grace period																																		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
Number of electric generation facilities																																											3
Number of electric generation facilities, owned by third party																																												1	1
Forecast over energy recovery																																														66,000,000
Forecast over energy recovery offset																																														66,000,000
Resource plan, proposed transfer																																										1,653
Annual load growth rate																																										1.40%
Regional enforcement entities		8
Customer power loss period	11 hours
Power threshold for cost methodology			500
Identified issues for written comments					9
Hybrid methodology, beneficiary pays cost allocation						50.00%
Hybrid methodology, postage stamp cost allocation						50.00%
One time payment, ATSI agreed to MISO				1,800,000
Annual Revenue requirements in Zone				16,000,000
Number of classes of regulatory proceedings				2
Losses incurred due to underfunding of contracts													35,000,000	500,000	34,500,000	11,500,000	11,400,000	100,000
Compliance filing period							60 days
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
Cost recovery, PP&E reclassified to Regulatory Assets											62,000,000	59,000,000
Return on equity for cost recovery								10.90%
Base return on equity for cost recovery								10.40%
Return on equity for cost recovery from RTO membership								0.50%
Remaining Recovery Period of Regulatory Assets								5 years
Amount of costs sought to be disallowed										$ 6,600,000
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