Derivative Instruments and Hedging Activities (Commodity Volumetric Activity) (Details)	Jun. 30, 2011 MW		Mar. 31, 2011 MW
Commodity Volumetric Activity - Sales of Baseload Generation (Numeric)
Baseload generation fleet capacity (in MW)			7,267
Commodity Volumetric Activity - Optimization of Intermediate and Peaking Generation (Numeric)
Intermediate and peaking generation fleet capacity (in MW)	3,501
Oil Swap [Member] | 2011 [Member] | Thousand of Barrels [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	48	[1],[2]
Oil Swap [Member] | 2012 [Member] | Thousand of Barrels [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	756	[2]
Oil Swap [Member] | 2013 [Member] | Thousand of Barrels [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	420	[2]
Oil Swap [Member] | 2014 [Member] | Thousand of Barrels [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	120
Net Power Sales [Member] | Non-option Contracts [Member] | 2011 [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(2,210)	[1],[3]
Net Power Sales [Member] | Non-option Contracts [Member] | 2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(2,006)	[3],[4]
Net Power Sales [Member] | Non-option Contracts [Member] | 2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(1,224)	[3],[4]
Net Power Sales [Member] | Non-option Contracts [Member] | 2014 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	408
Net Fuel Purchases [Member] | Non-option Contracts [Member] | 2011 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	20.7	[1],[3],[4]
Net Fuel Purchases [Member] | Non-option Contracts [Member] | 2012 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	13.5	[3],[4]
Net Fuel Purchases [Member] | Non-option Contracts [Member] | 2013 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	8.2	[3]
Net Fuel Purchases [Member] | Non-option Contracts [Member] | 2014 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	2.7
Energy Sales Contracts [Member] | 2011 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(6,876)	[1],[5],[6]
Energy Sales Contracts [Member] | 2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(9,918)	[5],[6]
Energy Sales Contracts [Member] | 2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(3,510)	[5],[6]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2011 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	5,019	[1],[5],[6]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	6,021	[5],[6]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	522	[5],[6]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2011 [Member] | GWh [Member]
Volumes of (Sales)/Purchase Contracts, Excluding FTRs, Basis and Capacity Contracts
Volumetric hedge volumes (in units)	337	[1],[5],[6],[7]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2012 [Member] | GWh [Member]
Volumes of (Sales)/Purchase Contracts, Excluding FTRs, Basis and Capacity Contracts
Volumetric hedge volumes (in units)	320	[5],[6],[7]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2013 [Member] | GWh [Member]
Volumes of (Sales)/Purchase Contracts, Excluding FTRs, Basis and Capacity Contracts
Volumetric hedge volumes (in units)	0	[5],[6],[7]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2011 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	1,662	[1],[5],[6]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	3,621	[5],[6]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	2,883	[5],[6]
Retail Gas Sales Contracts [Member] | 2011 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(3.3)	[1],[6]
Retail Gas Sales Contracts [Member] | 2012 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(7.0)	[6]
Retail Gas Sales Contracts [Member] | 2013 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(0.4)	[6]
Retail Gas Purchase Contracts [Member] | 2011 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	3.3	[1],[6]
Retail Gas Purchase Contracts [Member] | 2012 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	7.0	[6]
Retail Gas Purchase Contracts [Member] | 2013 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	0.4	[6]
FTRs [Member] | 2011 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
FTRs commodity positions (in GWh)	19,169	[1]
FTRs [Member] | 2012 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
FTRs commodity positions (in GWh)	15,297
FTRs [Member] | 2013 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
FTRs commodity positions (in GWh)	0
Power Basis Positions [Member] | 2011 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Power basis commodity positions (in GWh)	(8,478)	[1],[8]
Power Basis Positions [Member] | 2012 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Power basis commodity positions (in GWh)	(8,435)	[8]
Power Basis Positions [Member] | 2013 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Power basis commodity positions (in GWh)	(624)	[8]
Power Basis Positions [Member] | 2015 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Power basis commodity positions (in GWh)	205
Gas Basis Positions [Member] | 2011 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Gas basis commodity positions (in Bcf)	17.3	[1],[9]
Gas Basis Positions [Member] | 2012 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Gas basis commodity positions (in Bcf)	10.6	[9]
Gas Basis Positions [Member] | 2013 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Gas basis commodity positions (in Bcf)	(0.7)	[9]
Gas Basis Positions [Member] | Between 2014 And 2015 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts
Gas basis commodity positions (in Bcf)	(1.1)
Capacity [Member] | 2011 [Member] | MW-months [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(2,475)	[10],[11]
Capacity [Member] | 2012 [Member] | MW-months [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(3,542)	[10]
Capacity [Member] | 2013 [Member] | MW-months [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(1,005)	[10]
Capacity [Member] | Between 2014 and 2016 [Member] | MW-months [Member]
Expected Sales, in GWh, of Baseload Generation
Notional amount (in units)	(253)
2011 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Expected sales of baseload generation (in GWh)	27,118	[11]
2011 [Member] | Percent Unit [Member]
Expected Sales, in GWh, of Baseload Generation
Derivative sales, as percentage of expected baseload generation	91.00%	[1],[12],[13]
Total power sales, as percentage of expected baseload generation	98.00%	[1],[14]
Coal fuel purchases, as percentage of expected baseload generation	100.00%	[1],[15]
Nuclear fuel purchases, as percentage of expected baseload generation (in hundredths)	100.00%	[1],[15]
2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Expected sales of baseload generation (in GWh)	54,675
2012 [Member] | Percent Unit [Member]
Expected Sales, in GWh, of Baseload Generation
Derivative sales, as percentage of expected baseload generation	89.00%	[12],[13]
Total power sales, as percentage of expected baseload generation	97.00%	[14]
Coal fuel purchases, as percentage of expected baseload generation	96.00%	[15]
Nuclear fuel purchases, as percentage of expected baseload generation (in hundredths)	100.00%	[15]
2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Expected sales of baseload generation (in GWh)	54,364
2013 [Member] | Percent Unit [Member]
Expected Sales, in GWh, of Baseload Generation
Derivative sales, as percentage of expected baseload generation	61.00%	[12],[13]
Total power sales, as percentage of expected baseload generation	69.00%	[14]
Coal fuel purchases, as percentage of expected baseload generation	88.00%	[15]
Nuclear fuel purchases, as percentage of expected baseload generation (in hundredths)	100.00%	[15]
Between 2014 and 2016 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation
Volumes for sales contracts that deliver between 2014 and 2016 (in units)	2,964
Between 2014 and 2016 [Member] | Bcf [Member]
Expected Sales, in GWh, of Baseload Generation
Volumes for sales contracts that deliver between 2014 and 2016 (in units)	8.4

[1] Represents the balance of the current year.

[2] Volumes (in thousands of barrels) for derivative contracts used in support of this strategy that deliver in 2014 total 120.

[3] Included in these volumes are non-options and exercised option contracts that converted to non-option derivative contracts. Volumes associated with option contracts are not significant.

[4] Volumes for derivative contracts used in support of this strategy that deliver in 2014 total 408 GWh and 2.7 Bcf.

[5] Includes NPNS and contracts that are not derivatives, which receive accrual accounting.

[6] Net volumes for derivative contracts, excluding contracts that qualify for NPNS that deliver between 2014 and 2015 are not significant.

[7] PPL Energy Supply uses power and gas options, swaps and futures to hedge the volumetric risk associated with full-requirement sales contracts since the demand for power varies hourly. Volumes for option contracts factor in the probability of an option being exercised and may be less than the notional amount of the option.

[8] Net volumes that deliver in 2015 are 205 GWh.

[9] Net volumes that deliver in 2014 and 2015 are (1.1) Bcf.

[10] Net volumes that deliver between 2014 and 2016 are (253) MW-months.

[11] Represents expected sales for the balance of the current year.

[12] Excludes non-derivative contracts and contracts that qualify for NPNS. Volumes for option contracts factor in the probability of an option being exercised and may be less than the notional amount of the option.

[13] Volumes for derivative sales contracts that deliver between 2014 and 2016 total 2,964 GWh and 8.4 Bcf.

[14] Amount represents derivative and non-derivative contracts. Volumes for option contracts factor in the probability of an option being exercised and may be less than the notional amount of the option. Percentages are based on fixed-price contracts only.

[15] Coal and nuclear contracts receive accrual accounting treatment, as they are not derivative contracts. Percentages are based on both fixed- and variable-priced contracts.