Regulatory Matters (Details) (USD $)	6 Months Ended	0 Months Ended	1 Months Ended	6 Months Ended		1 Months Ended				0 Months Ended	6 Months Ended	0 Months Ended			31 Months Ended	0 Months Ended	6 Months Ended			0 Months Ended				0 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended		6 Months Ended						12 Months Ended							1 Months Ended	6 Months Ended			1 Months Ended			6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2013 entities	Jun. 07, 2013 FERC	Apr. 30, 2007 FERC kv	Jun. 30, 2013 FERC class	Jan. 21, 2010 FERC issues	May 31, 2013 FERC MOPR Reform	Dec. 07, 2012 FERC MOPR Reform exemption	Dec. 20, 2012 FERC Synchronous Condensers	Jun. 30, 2013 FERC PJM	Aug. 24, 2012 FERC PATH	Jun. 30, 2013 FERC PATH kv	Aug. 24, 2012 FERC PATH-Allegheny	Aug. 24, 2012 FERC Path-WV	Jun. 30, 2011 FERC Path-WV challenge	Dec. 31, 2012 FERC FES and AE Supply FTR Underfunding Complaint [Member] Minimum	Dec. 22, 2011 MARYLAND	Jun. 30, 2013 MARYLAND	Aug. 31, 2011 MARYLAND	Oct. 06, 2009 MARYLAND	Jun. 14, 2013 NEW JERSEY	Jun. 30, 2013 NEW JERSEY component bgs	Feb. 22, 2013 NEW JERSEY	Nov. 30, 2012 NEW JERSEY	Jun. 14, 2013 NEW JERSEY JCP&L	Jan. 31, 2013 OHIO Party	Aug. 31, 2011 OHIO proposals	Oct. 31, 2009 OHIO proposals	Jun. 30, 2013 OHIO plan	Dec. 31, 2009 OHIO	Dec. 12, 2012 OHIO questions	Jun. 30, 2013 OHIO Year 2012 MWh	Jun. 30, 2013 OHIO Year 2013 MWh	Jun. 30, 2013 OHIO Year 2014 MWh	Jun. 30, 2013 OHIO Annually Through 2025 MWh	Jun. 30, 2013 OHIO Annually Through 2018	Jun. 30, 2013 PENNSYLVANIA	Dec. 31, 2010 PENNSYLVANIA	Apr. 04, 2013 PENNSYLVANIA enhancement	Feb. 15, 2013 PENNSYLVANIA workgroup choice comment	Jan. 16, 2013 PENNSYLVANIA issues Party	May 31, 2011 PENNSYLVANIA	Apr. 29, 2011 PENNSYLVANIA questions	Jun. 30, 2013 PENNSYLVANIA Year 2013	Apr. 30, 2010 WEST VIRGINIA	Jun. 30, 2013 WEST VIRGINIA MW	Oct. 22, 2012 WEST VIRGINIA hearing	Feb. 28, 2011 WEST VIRGINIA Facilities	Feb. 28, 2011 WEST VIRGINIA City of New Martinsville entities	Feb. 28, 2011 WEST VIRGINIA Morgantown Energy entities	Oct. 31, 2006 California Claims Matters FERC Proceedings	Jun. 30, 2013 California Claims Matters FERC	Jun. 30, 2013 Yards Creek Pumped Storage Project FERC MW	Jun. 30, 2013 Yards Creek Pumped Storage Project FERC JCP&L	Jun. 30, 2013 The Seneca Pumped Storage Project FERC MW	Jun. 30, 2013 The Seneca Pumped Storage Project Relicensing	Jun. 30, 2013 Unfavorable Regulatory Action [Member] PENNSYLVANIA	Feb. 06, 2013 Unfavorable Regulatory Action [Member] PENNSYLVANIA
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																5 years	3 years
Maximum penalty assessed, in dollars per day per violation																	25,000
Expected increase in cost due to proposed plan																	106,000,000
Number of Supply Components																					2
Number of Basic Generation Services																					1
Requested increase in revenues																						603,000,000	31,500,000
Increase (Decrease) in Revenue Recovery Request																						112,000,000
Number of cost recovery choices																																							2
Load cap percentage minimum																												80.00%
Maximum trance award to a single supplier																												80.00%
Generation discount for low income customers																												6.00%
Recovery Period																												5 years
Costs avoided by customers																												360,000,000
Fund to assist low income customers																												12,000,000
ESP Extension Term																												2 years
Loss Contingency, New Claims Filed, Number																									2
Generation supply auction period, after approval																												3 years
Generation supply auction period, before approval																												1 year
Annual energy savings																															1,211,000	1,726,000	2,306,000	2,903,000
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%
Number of plans																												3
Portfolio Plan, Estimated Cost																												250,000,000
Portion of Revenue Obtained to be Received																												20.00%
Request for proposals conducted																										2	3
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, Range of Possible Loss, Maximum																																																								20,000,000	234,000,000
Number of parties not settled																																								1
Number of issues not settled																																								1
Annualized base rate increase																																												40,000,000
Storm Restoration Deferral Period																																												5 years
Number of public hearings held																																														2
Period of time to implement plan																																													6 months
Additional base rate increase																				20,600,000																								20,000,000
Recommend Reduction in Base Rates for Electric Service																								202,800,000
Decrease in ENEC rates																																												20,000,000
Number of electric generation facilities																																															3
Number of electric generation facilities, owned by third party																																																1	1
Power threshold for cost methodology			500
Compliance Filing, Hybrid Methodology, Beneficiary Pays Cost Allocation									50.00%
Denied Recovery Charges of Exit Fees				78,800,000
Identified issues for written comments					9
Annual Revenue requirements in Zone				16,000,000
Appeal Period		90 days
Number of classes of regulatory proceedings				2
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
Number of Formal Challenges														3
Auctioned Energy Price						59
Hydroelectric project																																																				400		451
Asset Transfer, Price								21,500,000
Ownership interest																																																					50.00%
Renewal length of operating license																																																					40 years
Period of cycle																																																							5 years
Number of Exemptions Added							2
Estimated Conversion Costs								60,000,000
Percent of Meters to be Installed																																				98.50%
Expected Cost of Meter Installations																																				1,250,000,000
Directed Questions for Investigation																														22												11
Number of Workgroups Established																																							5
Number of Comments Established																																							1
Number of Retail Market Enhancements																																						1
Regulatory Asset, Cost Recovery, Proposed Return on Equity										10.90%
Base Return On Equity										10.40%
Return On Equity Granted For Regional Transmission Organization Participation										0.50%
Remaining Recovery Period of Regulatory Assets										5 years
Revenues Lost of Which the Entity is Entitled															$ 62,000,000
Resource Plan, Proposed Transfer																																													1,476
Annual Load Growth Rate																																													1.40%
Compliance Filing, Hybrid Methodology, Postage Stamp Cost Allocation									50.00%
Period of Time to File Case																																													6 months
Regional Enforcement Entities	8