Derivative Instruments and Hedging Activities (Intro) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 MW	Dec. 31, 2011	Dec. 31, 2010
Master Netting Arrangements (Numeric) [Line Items]
Obligation to return cash collateral obligation under master netting arrangement	$ 112	$ 147
Cash collateral posted under master netting arrangements	32	29
Commodity Price Risk (Non-trading) [Line Items]
Baseload generation fleet capacity (in MW)	7,275
Intermediate and peaking generation fleet capacity (in MW)	3,316
Commodity Price Risk (Non-trading) - Monetization of Certain Full-Requirement Sales Contracts (Numeric) [Abstract]
Proceeds received from the monetization of certain full-requirement sales contracts			249
Fair value of NPNS contracts recorded due to the sale of certain full-requirements contracts			160
Realized pre-tax gains (losses) on NPNS contracts recorded due to sale of contracts			144
Portion of the fair value of NPNS contracts recorded that were not monetized			16
Dedesignation of cash flow hedges due to monetization of certain full-requirement sales contracts			(173)
Change in the fair value related to certain full-requirement sales contracts that were monetized			(39)
Pre-tax gain (loss) recorded on the monetization of certain full-requirement sales contracts			(68)
After-tax gain (loss) recorded on the monetization of certain full-requirement sales contracts			(40)
Commodity Price Risk (Non-trading) - Cash Flow Hedges (Numeric) [Abstract]
Year of expiration of the maximum maturity date of commodity price risk cash flow hedge contracts	2016
Net unrealized after-tax gains (losses) expected to be reclassified into earnings within 12 months related to commodity price risk cash flow hedge contracts	124
After-tax gains (losses) previously recorded in AOCI reclassified to earnings related to commodity price risk cash flow hedge contracts			(89)
No or insignificant amounts previously recorded in AOCI reclassified to earnings related to commodity price risk cash flow hedge contracts	insignificant	insignificant
No or immaterial hedge ineffectiveness related to commodity price risk cash flow hedge contracts	insignificant
Hedge ineffectiveness after-tax gains (losses) related to commodity price risk cash flow hedge contracts		(22)	(30)
After-tax gains (losses) resulting from hedge effectiveness testing failures related to commodity price risk cash flow hedge contracts			(82)
Commodity Price Risk (Non-trading) - Economic Activity (Numeric) [Abstract]
Year of expiration of the maximum maturity date of economic activity derivative contracts	2019
Fair value of commodity contracts classified as economic activity, net asset (liability)	346	(63)
Unregulated Retail Electric And Gas [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(17)	31	1
Wholesale Energy Marketing [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(311)	1,407	(805)
Fuel [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(14)	6	29
Energy Purchases [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	442	(1,123)	286
PPL Energy Supply LLC [Member]
Master Netting Arrangements (Numeric) [Line Items]
Obligation to return cash collateral obligation under master netting arrangement	112	147
Commodity Price Risk (Non-trading) [Line Items]
Baseload generation fleet capacity (in MW)	7,275
Intermediate and peaking generation fleet capacity (in MW)	3,316
Commodity Price Risk (Non-trading) - Monetization of Certain Full-Requirement Sales Contracts (Numeric) [Abstract]
Proceeds received from the monetization of certain full-requirement sales contracts			249
Fair value of NPNS contracts recorded due to the sale of certain full-requirements contracts			160
Realized pre-tax gains (losses) on NPNS contracts recorded due to sale of contracts			144
Portion of the fair value of NPNS contracts recorded that were not monetized			16
Dedesignation of cash flow hedges due to monetization of certain full-requirement sales contracts			(173)
Change in the fair value related to certain full-requirement sales contracts that were monetized			(39)
Pre-tax gain (loss) recorded on the monetization of certain full-requirement sales contracts			(68)
After-tax gain (loss) recorded on the monetization of certain full-requirement sales contracts			(40)
Commodity Price Risk (Non-trading) - Cash Flow Hedges (Numeric) [Abstract]
Year of expiration of the maximum maturity date of commodity price risk cash flow hedge contracts	2016
Net unrealized after-tax gains (losses) expected to be reclassified into earnings within 12 months related to commodity price risk cash flow hedge contracts	124
After-tax gains (losses) previously recorded in AOCI reclassified to earnings related to commodity price risk cash flow hedge contracts			(89)
No or insignificant amounts previously recorded in AOCI reclassified to earnings related to commodity price risk cash flow hedge contracts	insignificant	insignificant
No or immaterial hedge ineffectiveness related to commodity price risk cash flow hedge contracts	insignificant
Hedge ineffectiveness after-tax gains (losses) related to commodity price risk cash flow hedge contracts		(22)	(30)
After-tax gains (losses) resulting from hedge effectiveness testing failures related to commodity price risk cash flow hedge contracts			(82)
Commodity Price Risk (Non-trading) - Economic Activity (Numeric) [Abstract]
Year of expiration of the maximum maturity date of economic activity derivative contracts	2019
Fair value of commodity contracts classified as economic activity, net asset (liability)	346	(63)
PPL Energy Supply LLC [Member] | Unregulated Retail Electric And Gas [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(17)	31	1
PPL Energy Supply LLC [Member] | Wholesale Energy Marketing [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(311)	1,407	(805)
PPL Energy Supply LLC [Member] | Fuel [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	(14)	6	29
PPL Energy Supply LLC [Member] | Energy Purchases [Member]
Pre-tax Gains (Losses) of Economic Activity - Unregulated Business (Details) [Abstract]
Pre-tax gain (loss)	442	(1,123)	286
LG And E And KU Energy LLC [Member]
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral posted under master netting arrangements	32	29
Louisville Gas And Electric Co [Member]
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral posted under master netting arrangements	$ 32	$ 29