Commitments and Contingencies (Energy Purchases, Energy Sales, Other Commitments and Legal Matters) (Details) (USD $)	6 Months Ended	12 Months Ended			2 Months Ended	10 Months Ended	12 Months Ended		6 Months Ended	12 Months Ended					2 Months Ended	10 Months Ended	12 Months Ended			2 Months Ended	10 Months Ended	12 Months Ended			2 Months Ended	10 Months Ended	12 Months Ended
	Jun. 30, 2012 Integer	Dec. 31, 2012 Integer MW	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Power Purchase [Member]	Oct. 31, 2010 Power Purchase [Member]	Dec. 31, 2012 Power Purchase [Member]	Dec. 31, 2011 Power Purchase [Member]	Jun. 30, 2012 PPL Energy Supply LLC [Member] Integer	Dec. 31, 2012 PPL Energy Supply LLC [Member] Integer MW	Dec. 31, 2011 PPL Energy Supply LLC [Member]	Dec. 31, 2010 PPL Energy Supply LLC [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Integer MW	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Integer	Dec. 31, 2010 LG And E And KU Energy LLC [Member] Power Purchase [Member]	Oct. 31, 2010 LG And E And KU Energy LLC [Member] Power Purchase [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Power Purchase [Member]	Dec. 31, 2011 LG And E And KU Energy LLC [Member] Power Purchase [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Integer	Dec. 31, 2010 Louisville Gas And Electric Co [Member] Power Purchase [Member]	Oct. 31, 2010 Louisville Gas And Electric Co [Member] Power Purchase [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Power Purchase [Member]	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Power Purchase [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Integer	Dec. 31, 2010 Kentucky Utilities Co [Member] Power Purchase [Member]	Oct. 31, 2010 Kentucky Utilities Co [Member] Power Purchase [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Power Purchase [Member]	Dec. 31, 2011 Kentucky Utilities Co [Member] Power Purchase [Member]
Energy Purchase Commitments (Numeric) [Abstract]
Pre-tax charges incurred from coal contract modifications		$ 29,000,000								$ 29,000,000
Contingent potential proportionate share of OVEC's outstanding debt		135,000,000												135,000,000					93,000,000					42,000,000
Shortest term, in months, of PPL Electric PLR solicitations		5											5
Longest term, in years, of PPL Electric PLR solicitations		10											10
Hydroelectric License Commitments (Numeric) [Abstract]
Number of hydroelectric facilities owned by PPL Montana		11								11
Number of storage reservoirs owned by PPL Montana		1								1
Total term, in years, of the Kerr Dam project license		50								50
Term, in years, PPL Montana is required to operate the Kerr Dam project		30								30
The remaining amount PPL Montana has committed to spend on the Kerr Dam project through 2015		6,000,000								6,000,000
Number of open Memoranda of Understanding related to the issuance of the renewal license for the Missouri-Madison project		2								2
Number of dams related to the Missouri-Madison project for which Memoranda of Understanding exists		9								9
Estimate Of Remaining Commitment On Specific Missouri Madison Project		30,000,000								30,000,000
Unrecorded Unconditional Purchase Obligation [Line Items]
2013							30,000,000										30,000,000					21,000,000					9,000,000
2014							30,000,000										30,000,000					21,000,000					9,000,000
2015							30,000,000										30,000,000					21,000,000					9,000,000
2016							32,000,000										32,000,000					22,000,000					10,000,000
2017							32,000,000										32,000,000					22,000,000					10,000,000
Thereafter							884,000,000										884,000,000					612,000,000					272,000,000
Total future obligation							1,038,000,000										1,038,000,000					719,000,000					319,000,000
Purchases					6,000,000	24,000,000	29,000,000	32,000,000							6,000,000	24,000,000	29,000,000	32,000,000		4,000,000	17,000,000	20,000,000	22,000,000		2,000,000	7,000,000	9,000,000	10,000,000
Legal Matters - Montana Hydroelectric Litigation (Numeric) [Abstract]
Amount of compensation awarded in 2008 by the Montana District Court regarding PPL Montana's use of navigable riverbeds for periods 2000 to 2006		35,000,000								35,000,000
Amount of compensation awarded in 2008 by the Montana District Court regarding PPL Montana's use of navigable riverbeds for 2007		6,000,000								6,000,000
Interest rate per year		10.00%								10.00%
Pre-tax charge for the Montana Hydroelectric Litigation related to compensation for the periods between 2000 and the first quarter of 2010				56,000,000								56,000,000
After-tax charge for the Montana Hydroelectric Litigation related to compensation for the periods between 2000 and the first quarter of 2010				34,000,000								34,000,000
Portion of pre-tax charge for the Montana Hydroelectric Litigation related to compensation for the periods between 2000 and 2009				54,000,000								54,000,000
Portion of after-tax charge for the Montana Hydroelectric Litigation related to compensation for the periods between 2000 and 2009				32,000,000								32,000,000
Portion of pre-tax charge for the Montana Hydroelectric Litigation related to compensation for the period between 2000 and the first quarter of 2010 that is reflected in Other operation and maintenance				49,000,000								49,000,000
Portion of pre-tax charge for the Montana Hydroelectric Litigation related to compensation for the period between 2000 and the first quarter of 2010 that is reflected in Interest Expense				7,000,000								7,000,000
Contingency reversal during period, pre-tax			89,000,000								89,000,000
Contingency reversal during period, after-tax			53,000,000								53,000,000
Contingency reversal during period, impact to O&M			75,000,000								75,000,000
Contingency reversal during period, impact to interest expense			14,000,000								14,000,000
Legal Matters - Bankruptcy of Southern Montana Electric Generation and Transmission Cooperative, Inc. (Numeric) [Abstract]
Reserve related to the accounts receivable from a bankrupt counterparty		21,000,000								21,000,000
Total unsecured claim as a result of the termination of the SMGT contract		375,000,000								375,000,000
Legal Matters - Notice of Intent to Sue Colstrip Owners (Numeric) [Abstract]
Number of notices of intent to sue by the Sierra Club and Montana Environmental Information Center		4								4
Period to file lawsuits after applicable notice date (in days)		60								60
Settled Litigation - Spent Nuclear Fuel Litigation (Numeric) [Abstract]
PPL's share of settlement for spent nuclear fuel litigation			56,000,000								56,000,000
Regulatory Issues - Maryland Capacity Order (Numeric) [Abstract]
Number electric utilities ordered to enter into long term contracts		3								3			3
Capacity of natural gas-fired combined-cycle generating facility (in MW)		661								661			661
Pacific Northwest Markets (Numeric) [Abstract]
Number of claims remaining unsettled at period end	2								2
Amount for claims remaining unsettled at period end	73,000,000	50,000,000							73,000,000	50,000,000
Settlement amount reached with one of the parties		75,000								75,000
Amount of claim sought by City of Tacoma		23,000,000								23,000,000
Interest on amount of claim sought by City of Tacoma		9,000,000								9,000,000
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								3			3	3					3					3
Frequency, after initial filing, that a subsidiary is required to respond to the FERC market analysis information request (in years)		3								3			3	3					3					3
Regulatory Issues - Reliability Standards (Numeric) [Abstract]
Maximum per day penalties for reliability violations		$ 1,000,000								$ 1,000,000			$ 1,000,000	$ 1,000,000					$ 1,000,000					$ 1,000,000