Utility Rate Regulation (Regulatory Matters) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		12 Months Ended			1 Months Ended	12 Months Ended										12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2012 Integer	Dec. 31, 2011	Dec. 31, 2011 Kentucky August 2011 Storms [Member] Integer	Dec. 31, 2012 PPL Electric [Member] Integer	Dec. 31, 2011 PPL Electric [Member] Pennsylvania 2011 Storms [Member] Integer	Oct. 31, 2012 PPL Electric [Member] Pennsylvania 2012 Storms [Member]	Dec. 31, 2012 PPL Electric [Member] Pennsylvania 2012 Storms [Member]	Dec. 31, 2012 PPL Electric [Member] Distribution Rates [Member]	Dec. 31, 2012 LGE [Member]	Dec. 31, 2011 LGE [Member] Kentucky August 2011 Storms [Member] Integer	Dec. 31, 2012 LGE [Member] Electric Rates [Member]	Dec. 31, 2012 LGE [Member] Gas Rates [Member]	Dec. 31, 2012 KU [Member]	Dec. 31, 2012 KU [Member] Electric Rates [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Integer	Dec. 31, 2011 PPL Electric Utilities Corp [Member]	Dec. 31, 2011 PPL Electric Utilities Corp [Member] Pennsylvania 2011 Storms [Member] Integer	Oct. 31, 2012 PPL Electric Utilities Corp [Member] Pennsylvania 2012 Storms [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Pennsylvania 2012 Storms [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Distribution Rates [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Integer	Dec. 31, 2012 LG And E And KU Energy LLC [Member] LGE [Member]	Dec. 31, 2011 LG And E And KU Energy LLC [Member] LGE [Member] Kentucky August 2011 Storms [Member] Integer	Dec. 31, 2012 LG And E And KU Energy LLC [Member] LGE [Member] Electric Rates [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] LGE [Member] Gas Rates [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] KU [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] KU [Member] Electric Rates [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Integer	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Kentucky August 2011 Storms [Member] Integer	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Electric Rates [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Gas Rates [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] LGE [Member] Electric Rates [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates								$ 105			$ 62	$ 17		$ 82						$ 105				$ 62	$ 17		$ 82			$ 62	$ 17			$ 82
Dollar amount of increase to rates								71			34	15		51						71					15		51			34	15	34		51
Reduction in depreciation expense in 2013 as a result of lower weighted-average rates	19																				19							9					10
Return on equity increase resulting from approved increase to rates								10.40%	10.25%				10.25%							10.40%		10.25%				10.25%		10.25%					10.25%
Maximum period to file proposed Storm Damage Expense Rider (in days)				90											90
Regulatory Matters - Kentucky Activities - Certificate of Public Convenience and Necessity Filing (Numeric) [Abstract]
Number of scrubbers authorized to be built by applicable regulatory agency	2																				2							2
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Under Act 129, percentage reduction in electricity consumption by 2011	1.00%														1.00%
Under Act 129, percentage reduction in electricity consumption by 2013	3.00%														3.00%
Under Act 129, percentage reduction in peak demand electricity consumption by 2013	4.50%														4.50%
Number of hours that are the benchmark for demand reductions by 2013	100														100
Under Act 129, percentage cap on costs that can be recovered for implementation of EE and C plan	2.00%														2.00%
Number of years EDCs have to comply with consumption reduction target	3														3
Under Act 129, percentage reduction in electricity target for the company under the Phase II program	2.10%														2.10%
Minimum term of long term supply contract under Act 129 (in years)	4														4
Maximum term of long term supply contract under Act 129 (in years)	20														20
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%														25.00%
Regulatory Matters - Pennsylvania Activities - Smart Meter Rider (Numeric) [Abstract]
Maximum number of years the cost of smart meters can be depreciated	15														15
Estimated cost for studies on smart meter capabilities	38														38
The time period covered by cost projection for studies on smart meter capabilities (in years)	5														5
Regulatory Matters - Pennsylvania Activities - PUC Investigation of Retail Market (Numeric) [Abstract]
Number of phases of a PUC investigation of retail electricity market	2														2
Number of possible models for the default service end state	3														3
Period to provide comment on the PUC implementation order (in days)	30														30
Regulatory Matters - Pennsylvania Activities - Legislation - Regulatory Procedures and Mechanisms (Numeric) [Abstract]
Number of ratemaking mechanisms authorized for PUC approval	2														2
Minimum term for Long Term Infrastructure Improvement Plan (in years)	5														5
Maximum term for Long Term Infrastructure Improvement Plan (in years)	10														10
Regulatory Matters - Storm Costs (Numeric) [Abstract]
Number of customers impacted by storm										139,000													139,000						139,000
Total storm restoration costs incurred					84	66	81										84	66	81
Storm restoration costs recorded to statement of income					54	50	61										54	50	61
Total probable insurance recoveries recorded					26.50		18.25										26.50		18.25
Total probable insurance recoveries recorded to statement of income					16		14										16		14
Amount of regulatory asset established					25		28			8							25		28				8						8
Period over which storm costs will be recovered (in years)			5		5					5							5												5
Regulatory Matters - Federal Matters - FERC Formula Rates (Numeric) [Abstract]
Requested recovery period (in years)	34														34
Regulatory asset amount recorded related to certain deferred state tax assets	52	53													52	53
Regulatory Matters - U.K. Activities - Ofgem Review of Line Loss Calculation (Numeric) [Abstract]
WPD's projected cost for compliance with overhead electricity standards	94	170
Number of potential changes cited in a consultation paper issued by Ofgem	2
WPD's credit to income statement for Distribution Price Control Review 4 liability	79
WPD's credit to income statement for Distribution Price Control Review 5 liability	$ 11