Commitments and Contingencies (Environmental Matter and Other) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012 Gallons MW Years PartsPerBillion Integer
Environmental Matters - Domestic - Air - Cross State Air Pollution Rule formerly Clean Air Transport Rule (Numeric) [Abstract]
Number of phases CSAPR will be implemented	2
Environmental Matters - Domestic - Air - National Ambient Air Quality Standards [Abstract]
Standard for sulfur dioxide emissions (in hours)	1
Environmental Matters - Domestic - Air - Mercury and Other Hazardous Air Pollutants (Numeric) [Abstract]
Period for compliance with final MACT standards (in years)	3
Possible period of extension to comply with final MACT standards (in years)	1
Carrying value of Corette plant in Montana that is being moved to long-term reserve status	$ 67,000,000
Environmental Matters - Domestic - Air - Greenhouse Gas Regulations and Tort Litigation (Numeric) [Abstract]
Number of northeastern states that signed a Memorandum of Understanding that established RGGI	10
Minimum capacity of electric power plants that are impacted by RGGI's emissions stabilization program (in MW)	25
Percentage reduction by 2019 in carbon dioxide emissions under RGGI	10.00%
Maximum percentage reduction in greenhouse gas emissions by implementing actions identified in a Pennsylvania 2009 report	30.00%
Proposed mandatory percentage improvement at power plants	5.00%
Number of western states that are members of the WCI	11
WCI's target percentage for reducing carbon dioxide emissions	15.00%
Number of electric utility companies affected by a September 2009 U.S. Court of Appeals for the Second Circuit decision	5
Number of companies cited in May 2011 Mississippi court filing	87
Number of indirect subsidaries cited in a May 2011 Mississippi court filing	3
Environmental Matters - Domestic - Air - Renewable Energy Legislation (Numeric) [Abstract]
Proposed minimum percentage of electricity sales supplied from qualified resources by 2015	24.00%
Proposed percentage increase per year from 2016 to 2035 of electricity sales supplied from qualified resources	3.00%
Proposed maximum percentage of electricity sales supplied from qualified resources by 2035	84.00%
Environmental Matters - Domestic - Water/Waste - Coal Combustion Residuals (Numeric) [Abstract]
Number of approaches proposed by EPA in June 2010 to regulate CCRs	2
Environmental Matters - Domestic - Water/Waste - Martins Creek Fly Ash Release (Numeric) [Abstract]
Gallons of water released at the Martins Creek plant in 2005 that contained fly ash	100,000,000
Number of coal-fired generating units at the Martins Creek plant at the time of fly ash release	2
Capacity of each coal-fired generating unit at the Martins Creek plant (in MW)	150
Amounts incurred through period end for remediation and related costs related to 2005 Martins Creek fly ash release	28,000,000
Environmental Matters - Domestic - Water/Waste - Seepages and Groundwater Infiltration - Pennsylvania, Montana and Kentucky (Numeric) [Abstract]
Number of plaintiffs that filed a lawsuit against the Colstrip plant owners in 2007 for seepage issues	6
Period to complete a settlement (in days)	60
Period for PPL Montana to provide financial assurance to Montana Department of Environmental Quality (in years)	5
Environmental Matters - Domestic - Water/Waste - Clean Water Act 316(b) (Numeric) [Abstract]
Number of Notices of Data Availability issued by EPA	2
Number of requirements under proposed EPA rule regarding reducing impact to aquatic organisms	2
Number of factors to make a site-specific determination	9
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
Number of alternatives provided to the DEP to address fish kill issues at Brunner Island	3
Other - Nuclear Insurance (Numeric) [Abstract]
Maximum amount of insured property damage losses at nuclear station	2,750,000,000
Maximum assessment for retroactive premiums for nuclear outage insurance coverage	48,000,000
Maximum public liability for claims resulting an incident at nuclear station	12,600,000,000
Maximum amount that could be assessed resulting from an incident at nuclear station	235,000,000
Maximum amount payable per year resulting from an incident at nuclear station	35,000,000
Other - Employee Relations (Numeric) [Abstract]
Employee labor contract period (in years)	3
Employee labor contract wage increase	2.50%
Employee labor contract wage subsequent increase	2.50%
Number of employees covered by contract	70
PPL Energy Supply LLC [Member]
Environmental Matters - Domestic - Air - Cross State Air Pollution Rule formerly Clean Air Transport Rule (Numeric) [Abstract]
Number of phases CSAPR will be implemented	2
Environmental Matters - Domestic - Air - National Ambient Air Quality Standards [Abstract]
Standard for sulfur dioxide emissions (in hours)	1
Environmental Matters - Domestic - Air - Mercury and Other Hazardous Air Pollutants (Numeric) [Abstract]
Period for compliance with final MACT standards (in years)	3
Possible period of extension to comply with final MACT standards (in years)	1
Carrying value of Corette plant in Montana that is being moved to long-term reserve status	67,000,000
Environmental Matters - Domestic - Air - Greenhouse Gas Regulations and Tort Litigation (Numeric) [Abstract]
Number of northeastern states that signed a Memorandum of Understanding that established RGGI	10
Minimum capacity of electric power plants that are impacted by RGGI's emissions stabilization program (in MW)	25
Percentage reduction by 2019 in carbon dioxide emissions under RGGI	10.00%
Maximum percentage reduction in greenhouse gas emissions by implementing actions identified in a Pennsylvania 2009 report	30.00%
Proposed mandatory percentage improvement at power plants	5.00%
Number of western states that are members of the WCI	11
WCI's target percentage for reducing carbon dioxide emissions	15.00%
Number of electric utility companies affected by a September 2009 U.S. Court of Appeals for the Second Circuit decision	5
Number of companies cited in May 2011 Mississippi court filing	87
Environmental Matters - Domestic - Air - Renewable Energy Legislation (Numeric) [Abstract]
Proposed minimum percentage of electricity sales supplied from qualified resources by 2015	24.00%
Proposed percentage increase per year from 2016 to 2035 of electricity sales supplied from qualified resources	3.00%
Proposed maximum percentage of electricity sales supplied from qualified resources by 2035	84.00%
Environmental Matters - Domestic - Water/Waste - Coal Combustion Residuals (Numeric) [Abstract]
Number of approaches proposed by EPA in June 2010 to regulate CCRs	2
Environmental Matters - Domestic - Water/Waste - Martins Creek Fly Ash Release (Numeric) [Abstract]
Gallons of water released at the Martins Creek plant in 2005 that contained fly ash	100,000,000
Number of coal-fired generating units at the Martins Creek plant at the time of fly ash release	2
Capacity of each coal-fired generating unit at the Martins Creek plant (in MW)	150
Amounts incurred through period end for remediation and related costs related to 2005 Martins Creek fly ash release	28,000,000
Environmental Matters - Domestic - Water/Waste - Seepages and Groundwater Infiltration - Pennsylvania, Montana and Kentucky (Numeric) [Abstract]
Number of plaintiffs that filed a lawsuit against the Colstrip plant owners in 2007 for seepage issues	6
Period to complete a settlement (in days)	60
Period for PPL Montana to provide financial assurance to Montana Department of Environmental Quality (in years)	5
Environmental Matters - Domestic - Water/Waste - Clean Water Act 316(b) (Numeric) [Abstract]
Number of Notices of Data Availability issued by EPA	2
Number of requirements under proposed EPA rule regarding reducing impact to aquatic organisms	2
Number of factors to make a site-specific determination	9
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
Number of alternatives provided to the DEP to address fish kill issues at Brunner Island	3
Other - Nuclear Insurance (Numeric) [Abstract]
Maximum amount of insured property damage losses at nuclear station	2,750,000,000
Maximum assessment for retroactive premiums for nuclear outage insurance coverage	48,000,000
Maximum public liability for claims resulting an incident at nuclear station	12,600,000,000
Maximum amount that could be assessed resulting from an incident at nuclear station	235,000,000
Maximum amount payable per year resulting from an incident at nuclear station	$ 35,000,000
PPL Electric Utilities Corp [Member]
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
LG And E And KU Energy LLC [Member]
Environmental Matters - Domestic - Air - Cross State Air Pollution Rule formerly Clean Air Transport Rule (Numeric) [Abstract]
Number of phases CSAPR will be implemented	2
Environmental Matters - Domestic - Air - National Ambient Air Quality Standards [Abstract]
Standard for sulfur dioxide emissions (in hours)	1
Environmental Matters - Domestic - Air - Mercury and Other Hazardous Air Pollutants (Numeric) [Abstract]
Period for compliance with final MACT standards (in years)	3
Possible period of extension to comply with final MACT standards (in years)	1
Environmental Matters - Domestic - Air - Greenhouse Gas Regulations and Tort Litigation (Numeric) [Abstract]
Number of northeastern states that signed a Memorandum of Understanding that established RGGI	10
Minimum capacity of electric power plants that are impacted by RGGI's emissions stabilization program (in MW)	25
Percentage reduction by 2019 in carbon dioxide emissions under RGGI	10.00%
Maximum percentage reduction in greenhouse gas emissions by implementing actions identified in a Pennsylvania 2009 report	30.00%
Proposed mandatory percentage improvement at power plants	5.00%
Number of western states that are members of the WCI	11
WCI's target percentage for reducing carbon dioxide emissions	15.00%
Number of electric utility companies affected by a September 2009 U.S. Court of Appeals for the Second Circuit decision	5
Number of companies cited in May 2011 Mississippi court filing	87
Number of indirect subsidaries cited in a May 2011 Mississippi court filing	3
Environmental Matters - Domestic - Air - Renewable Energy Legislation (Numeric) [Abstract]
Proposed minimum percentage of electricity sales supplied from qualified resources by 2015	24.00%
Proposed percentage increase per year from 2016 to 2035 of electricity sales supplied from qualified resources	3.00%
Proposed maximum percentage of electricity sales supplied from qualified resources by 2035	84.00%
Environmental Matters - Domestic - Water/Waste - Coal Combustion Residuals (Numeric) [Abstract]
Number of approaches proposed by EPA in June 2010 to regulate CCRs	2
Environmental Matters - Domestic - Water/Waste - Clean Water Act 316(b) (Numeric) [Abstract]
Number of Notices of Data Availability issued by EPA	2
Number of requirements under proposed EPA rule regarding reducing impact to aquatic organisms	2
Number of factors to make a site-specific determination	9
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
Other - Employee Relations (Numeric) [Abstract]
Employee labor contract period (in years)	3
Employee labor contract wage increase	2.50%
Employee labor contract wage subsequent increase	2.50%
Number of employees covered by contract	70
Louisville Gas And Electric Co [Member]
Environmental Matters - Domestic - Air - Cross State Air Pollution Rule formerly Clean Air Transport Rule (Numeric) [Abstract]
Number of phases CSAPR will be implemented	2
Environmental Matters - Domestic - Air - National Ambient Air Quality Standards [Abstract]
Standard for sulfur dioxide emissions (in hours)	1
Environmental Matters - Domestic - Air - Mercury and Other Hazardous Air Pollutants (Numeric) [Abstract]
Period for compliance with final MACT standards (in years)	3
Possible period of extension to comply with final MACT standards (in years)	1
Environmental Matters - Domestic - Air - Greenhouse Gas Regulations and Tort Litigation (Numeric) [Abstract]
Number of northeastern states that signed a Memorandum of Understanding that established RGGI	10
Minimum capacity of electric power plants that are impacted by RGGI's emissions stabilization program (in MW)	25
Percentage reduction by 2019 in carbon dioxide emissions under RGGI	10.00%
Maximum percentage reduction in greenhouse gas emissions by implementing actions identified in a Pennsylvania 2009 report	30.00%
Proposed mandatory percentage improvement at power plants	5.00%
Number of western states that are members of the WCI	11
WCI's target percentage for reducing carbon dioxide emissions	15.00%
Number of electric utility companies affected by a September 2009 U.S. Court of Appeals for the Second Circuit decision	5
Number of companies cited in May 2011 Mississippi court filing	87
Environmental Matters - Domestic - Air - Renewable Energy Legislation (Numeric) [Abstract]
Proposed minimum percentage of electricity sales supplied from qualified resources by 2015	24.00%
Proposed percentage increase per year from 2016 to 2035 of electricity sales supplied from qualified resources	3.00%
Proposed maximum percentage of electricity sales supplied from qualified resources by 2035	84.00%
Environmental Matters - Domestic - Water/Waste - Coal Combustion Residuals (Numeric) [Abstract]
Number of approaches proposed by EPA in June 2010 to regulate CCRs	2
Environmental Matters - Domestic - Water/Waste - Clean Water Act 316(b) (Numeric) [Abstract]
Number of Notices of Data Availability issued by EPA	2
Number of requirements under proposed EPA rule regarding reducing impact to aquatic organisms	2
Number of factors to make a site-specific determination	9
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
Kentucky Utilities Co [Member]
Environmental Matters - Domestic - Air - Cross State Air Pollution Rule formerly Clean Air Transport Rule (Numeric) [Abstract]
Number of phases CSAPR will be implemented	2
Environmental Matters - Domestic - Air - National Ambient Air Quality Standards [Abstract]
Standard for sulfur dioxide emissions (in hours)	1
Environmental Matters - Domestic - Air - Mercury and Other Hazardous Air Pollutants (Numeric) [Abstract]
Period for compliance with final MACT standards (in years)	3
Possible period of extension to comply with final MACT standards (in years)	1
Environmental Matters - Domestic - Air - Greenhouse Gas Regulations and Tort Litigation (Numeric) [Abstract]
Number of northeastern states that signed a Memorandum of Understanding that established RGGI	10
Minimum capacity of electric power plants that are impacted by RGGI's emissions stabilization program (in MW)	25
Percentage reduction by 2019 in carbon dioxide emissions under RGGI	10.00%
Maximum percentage reduction in greenhouse gas emissions by implementing actions identified in a Pennsylvania 2009 report	30.00%
Proposed mandatory percentage improvement at power plants	5.00%
Number of western states that are members of the WCI	11
WCI's target percentage for reducing carbon dioxide emissions	15.00%
Number of electric utility companies affected by a September 2009 U.S. Court of Appeals for the Second Circuit decision	5
Number of companies cited in May 2011 Mississippi court filing	87
Environmental Matters - Domestic - Air - Renewable Energy Legislation (Numeric) [Abstract]
Proposed minimum percentage of electricity sales supplied from qualified resources by 2015	24.00%
Proposed percentage increase per year from 2016 to 2035 of electricity sales supplied from qualified resources	3.00%
Proposed maximum percentage of electricity sales supplied from qualified resources by 2035	84.00%
Environmental Matters - Domestic - Water/Waste - Coal Combustion Residuals (Numeric) [Abstract]
Number of approaches proposed by EPA in June 2010 to regulate CCRs	2
Environmental Matters - Domestic - Water/Waste - Clean Water Act 316(b) (Numeric) [Abstract]
Number of Notices of Data Availability issued by EPA	2
Number of requirements under proposed EPA rule regarding reducing impact to aquatic organisms	2
Number of factors to make a site-specific determination	9
Environmental Matters - Domestic - Water/Waste - Other Issues (Numeric) [Abstract]
EPA's current drinking water standard relating to arsenic (in parts per billion)	10
Increase in cancer risk related to arsenic in drinking water	20 times
The EPA's proposed drinking water standard relating to arsenic (in parts per billion)	0.1
Other - Employee Relations (Numeric) [Abstract]
Employee labor contract period (in years)	3
Employee labor contract wage increase	2.50%
Employee labor contract wage subsequent increase	2.50%
Number of employees covered by contract	70