Fair Value Measurements and Credit Concentration (Net Assets and Liabilities Measured on Recurring Basis Level 3 Significant Unobservable Inputs) (Details) (Level 3 [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	30	[1]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	14
Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	100.00%	[2]
Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	20.00%	[2]
Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	69.00%	[2]
Energy Commodities, Net [Member] | Power Sales Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	(7)	[3]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	(4)
Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	61.00%	[2]
Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	24.00%	[2]
Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	25.00%	[2]
Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	11	[4]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	11
Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Customer migration	80.00%	[2]
Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Customer migration	13.00%	[2]
Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Customer migration	34.00%	[2]
Auction Rate Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	15	[5]
Fair Value Inputs [Abstract]
Weighted average contractual maturity of auction rate securites (in years)	26
Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	80.00%	[2]
Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	54.00%	[2]
Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	65.00%	[2]
Cross Currency Swaps [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	10	[6]
Cross Currency Swaps [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Credit valuation adjustment	37.00%	[2]
Cross Currency Swaps [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Credit valuation adjustment	25.00%	[2]
Cross Currency Swaps [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Credit valuation adjustment	32.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	30	[1]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	14
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	100.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	20.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Retail Natural Gas Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Observable wholesale prices used as proxy for retail delivery points	69.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Power Sales Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	(7)	[3]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	(4)
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	61.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	24.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Power Sales Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Basis price between delivery points	25.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	11	[4]
Fair Value Inputs [Abstract]
Fair value scheduled to deliver within next 12 months	11
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Customer migration	80.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Customer migration	13.00%	[2]
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Full Requirement Sales Contracts [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Customer migration	34.00%	[2]
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair value of net asset and (liability)	12	[5]
Fair Value Inputs [Abstract]
Weighted average contractual maturity of auction rate securites (in years)	26
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	80.00%	[2]
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	61.00%	[2]
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Modeled from SIFMA Index	66.00%	[2]

[1] Retail natural gas sales contracts extend through 2017. $##D<RetailGasDeliverL3CYFVMCCCorp> million of the fair value is scheduled to deliver within the next 12 months. As the forward price of natural gas increases/(decreases), the fair value of the contracts (decreases)/increases.

[2] For energy commodities and auction rate securities, the range and weighted average represent the percentage of fair value derived from the unobservable inputs. For cross-currency swaps, the range and weighted average represent the percentage decrease in fair value due to the unobservable inputs used in the model to calculate the credit valuation adjustment.

[3] Power sales contracts extend through 2017. $##D<ElectricDeliverL3CYFVMCCCorp> million of the fair value is scheduled to deliver within the next 12 months. As the forward price of basis increases/(decreases), the fair value of the contracts (decreases)/increases.

[4] Full-requirement sales contracts extend through 2013. $11 million of the fair value is scheduled to deliver within the next 12 months. As customer migration increases/(decreases), the fair value of the contracts decreases/(increases).

[5] Auction rate securities have a weighted average contractual maturity of ##D<ArsWeightedAvgMaturityCYFVMCCCorp> years. The model used to calculate fair value incorporates an assumption that the auctions will continue to fail. As the modeled forward rates of the SIFMA index increase/(decrease), the fair value of the securities increases/(decreases).

[6] Cross-currency swaps extend through 2021. The credit valuation adjustment incorporates projected probabilities of default and estimated recovery rates. As the credit valuation adjustment increases/(decreases), the fair value of the swaps (decreases)/increases.