Regulatory Matters (Details) (USD $)	6 Months Ended					12 Months Ended		6 Months Ended				6 Months Ended	12 Months Ended						6 Months Ended			6 Months Ended	3 Months Ended			6 Months Ended	60 Months Ended		6 Months Ended		1 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011 2015 WEST VIRGINIA	Jun. 30, 2011 2020 WEST VIRGINIA	Jun. 30, 2011 2025 WEST VIRGINIA	Jun. 30, 2011 MARYLAND	Dec. 31, 2007 MARYLAND	Oct. 06, 2009 MARYLAND	Jun. 30, 2011 NEW JERSEY	Jan. 23, 2009 OE OHIO	Jan. 23, 2009 CEI OHIO	Jan. 23, 2009 TE OHIO	Jun. 30, 2011 OHIO	Dec. 31, 2013 OHIO MWH	Dec. 31, 2012 OHIO MWH	Dec. 31, 2011 OHIO MWH	Dec. 31, 2010 OHIO MWH	Dec. 31, 2009 OHIO MWH	Jan. 23, 2009 OHIO	Jun. 30, 2011 PENNSYLVANIA	May 31, 2013 PENNSYLVANIA	May 31, 2011 PENNSYLVANIA	Jun. 30, 2011 WEST VIRGINIA	Jun. 30, 2011 California Claims Matters	Jun. 30, 2011 The Seneca Pumped Storage Project Relicensing	Jun. 30, 2011 The Seneca Pumped Storage Project FERC MWH	Jun. 30, 2011 PJM Calculation Error FERC	Mar. 31, 2010 PJM Calculation Error FERC	Jun. 16, 2011 PJM Calculation Error FERC	Jun. 30, 2011 FERC	Jun. 30, 2011 FERC TRAIL KV	Nov. 19, 2010 FERC PATH	Jun. 30, 2011 FERC PATH KV	Jun. 30, 2011 Penelec	Jun. 30, 2011 Met-Ed	Apr. 29, 2010 Met-Ed KV
Regulatory Matters [Line Items]
Proposed electric consumption reduction percentage					10.00%
Proposed electric demand reduction percentage					15.00%
Increase electric distribution rates									$ 68,900,000	$ 29,200,000	$ 38,500,000							$ 136,600,000
Total annual energy savings													530,000	470,000	410,000	290,000	166,000
Utilities required to reduce peak demand in 2009																			1.00%
Utilities Required To Additionally Reduce Peak Demand												0.75%
Load Served From Renewable Energy Resources																0.50%	0.25%
Marginal transmission losses																			254,000,000														65,000,000	189,000,000
Approximate increase in retail rates																						95,000,000
Revised decommissioning costs								736,000,000
Number of settlements for which liability charges are fix																													9
Number of settlements for which relevant payment has been made																													8
New Voltage transmission facilities across PJM and a zonal transmission rate (In KV)																														500		765
One time payment, ATSI agreed to MISO																													1,800,000
Annual Revenue requirements in Zone																													15,000,000
Annual Revenue Requirements In Zone Assigned for year to ATSI																													1,800,000
Net underpayments from PJM to MISO																										5,000,000	130,000,000
Maximum Cost Incurred Due To Improper Market To Market Settlements																										25,000,000
Number of complaints for which order approving settlement is issued																												3
Return on equity granted as incentive rider																															1.50%
Return on equity granted for RTO participation																															0.50%
Maximum amount of penalty assessed per day per violation					25,000,000
Number of programs for residential customers						7
Minimum reduction in Utilities peak demand																				4.50%
Description of vegetation encroachment event																																			230
Hydroelectric project																									451
Load cap percentage minimum												80.00%
Specified minimum percentage of electricity sold to retail customers		10.00%	15.00%	25.00%
Expenditures for cost recovery program							101,000,000
Reduction in recovery of societal benefits charge								800,000
Decrease in ENEC rates																						20,000,000
Annualized Base Rate Increase																						40,000,000
Fund to assist low income customers												12,000,000
Settlement proposal claims																							190,000,000
Minimum reduction in Utilities reduce energy consumption																				3.00%	1.00%
Target installation smart meter																			25,000
Generation discount for low income customers												6.00%
Grace period	30 months
Duration of Plan Approved As Per Order																	3 years
Smart meter infrastructure deployed																			725,000
Additional base rate increase																						20,000,000
Contemplated deployment of smart meter infrastructure																			375,000
Period of Cycle						5 years																		5 years
Period of the portfolio plans filed seeking approval for the program																	3 years
Costs avoided by customers												360,000,000
Recovery period for expenditures for cost recovery program							6 years
Requested amendment deemed to be necessary																	1
Number of companies involved in compliance with yet to be defined modified benchmarks																	2
Assessment period costs																			$ 29,500,000
Assessment period	24 months
Comment period	30 days