Commitments and Contingencies (Energy Purchases, Energy Sales, Other Commitments, Legal Matters and Regulatory Issues) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014 mi Integer MW Y
Legal Matters - Sierra Club Litigation (Numeric) [Abstract]
Number of separate claims included in the complaint against PPL Montana	39
Average requested amount, per day per violation, of injuctive relief and civil penalities	$ 36,000
Amount of civil penalities to be used for beneficial mitigation projects	100,000
Estimated number of post-2000 projects alleged not to be in compliance with the Clean Air Act	40
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit	6
Number of miles within plant that would include a class of residents	4
Regulatory Issues - Maryland Capacity Order (Numeric) [Abstract]
Number electric utilities ordered to enter into long term contracts	3
Capacity of natural gas-fired combined-cycle generating facility (in MW)	661
Regulatory Issues - Pacific Northwest Markets (Numeric) [Abstract]
Amount for claims remaining unsettled at period end	50,000,000
Settlement amount reached with one of the parties	75,000
Amount of claim sought by City of Tacoma	23,000,000
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	1,000,000
PPL Energy Supply LLC [Member]
Legal Matters - Sierra Club Litigation (Numeric) [Abstract]
Number of separate claims included in the complaint against PPL Montana	39
Average requested amount, per day per violation, of injuctive relief and civil penalities	36,000
Amount of civil penalities to be used for beneficial mitigation projects	100,000
Estimated number of post-2000 projects alleged not to be in compliance with the Clean Air Act	40
Regulatory Issues - Maryland Capacity Order (Numeric) [Abstract]
Number electric utilities ordered to enter into long term contracts	3
Capacity of natural gas-fired combined-cycle generating facility (in MW)	661
Regulatory Issues - Pacific Northwest Markets (Numeric) [Abstract]
Amount for claims remaining unsettled at period end	50,000,000
Settlement amount reached with one of the parties	75,000
Amount of claim sought by City of Tacoma	23,000,000
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	1,000,000
PPL Electric Utilities Corp [Member]
Regulatory Issues - Maryland Capacity Order (Numeric) [Abstract]
Number electric utilities ordered to enter into long term contracts	3
Capacity of natural gas-fired combined-cycle generating facility (in MW)	661
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	1,000,000
LG And E And KU Energy LLC [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit	6
Number of miles within plant that would include a class of residents	4
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	1,000,000
Louisville Gas And Electric Co [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit	6
Number of miles within plant that would include a class of residents	4
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	1,000,000
Kentucky Utilities Co [Member]
Regulatory Issues - FERC Market-Based Rate Authority (Numeric) [Abstract]
Time from December 1998 that a subsidiary was required to respond to the FERC market analysis information request (in years)	3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)	3
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations	$ 1,000,000