Derivative Instruments and Hedging Activities (Commodity Volumetric Activity) (Details)	3 Months Ended
	Mar. 31, 2012 Integer MW
Commodity Volumetric Activity (Numeric) [Abstract]
Number of strategies used to maximize wholesale energy portfolio value	4
Commodity Volumetric Activity - Sales of Baseload Generation (Numeric) [Abstract]
Baseload generation fleet capacity (in MW)	7,252
Commodity Volumetric Activity - Proprietary Trading Activity (Numeric) [Abstract]
Insignificant or no proprietary trading positions	insignificant
Commodity Volumetric Activity - Optimization of Intermediate and Peaking Generation (Numeric) [Abstract]
Intermediate and peaking generation fleet capacity (in MW)	3,256
2012 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation [Abstract]
Expected sales of baseload generation (in GWh)	39,733	[1]
2012 [Member] | Percent Unit [Member]
Percentage Of Expected Baseload Generation Sales [Abstract]
Derivative sales, as percentage of expected baseload generation	91.00%	[2],[3]
Total power sales, as percentage of expected baseload generation	95.00%	[3],[4]
Coal fuel purchases, as percentage of expected baseload generation	100.00%	[3],[5]
Nuclear fuel purchases, as percentage of expected baseload generation	100.00%	[3],[5]
2013 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation [Abstract]
Expected sales of baseload generation (in GWh)	53,136
2013 [Member] | Percent Unit [Member]
Percentage Of Expected Baseload Generation Sales [Abstract]
Derivative sales, as percentage of expected baseload generation	75.00%	[2]
Total power sales, as percentage of expected baseload generation	82.00%	[4]
Coal fuel purchases, as percentage of expected baseload generation	97.00%	[5]
Nuclear fuel purchases, as percentage of expected baseload generation	100.00%	[5]
2014 [Member] | GWh [Member]
Expected Sales, in GWh, of Baseload Generation [Abstract]
Expected sales of baseload generation (in GWh)	53,502
2014 [Member] | Percent Unit [Member]
Percentage Of Expected Baseload Generation Sales [Abstract]
Derivative sales, as percentage of expected baseload generation	8.00%	[2],[6]
Total power sales, as percentage of expected baseload generation	13.00%	[4]
Coal fuel purchases, as percentage of expected baseload generation	70.00%	[5]
Nuclear fuel purchases, as percentage of expected baseload generation	100.00%	[5]
Future Years [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Volumes for sales contracts that deliver in future years	1,635
Future Years [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Volumes for sales contracts that deliver in future years	20.2
Capacity [Member] | MW-Months [Member]
Capacity Positions [Abstract]
Capacity positions that deliver in future periods (in MW-months)	989
Capacity [Member] | 2012 [Member] | MW-Months [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(7,102)
Capacity [Member] | 2013 [Member] | MW-Months [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(3,366)
Capacity [Member] | 2014 [Member] | MW-Months [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(2,578)
Financial Transmission Rights [Member] | 2012 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
FTRs (in GWh)	7,207	[3]
Financial Transmission Rights [Member] | 2013 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
FTRs (in GWh)	0
Financial Transmission Rights [Member] | 2014 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
FTRs (in GWh)	0
Power Basis Positions [Member] | 2012 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Power basis positions (in GWh)	(13,316)	[3],[7]
Power Basis Positions [Member] | 2013 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Power basis positions (in GWh)	(8,244)
Power Basis Positions [Member] | 2014 [Member] | GWh [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Power basis positions (in GWh)	(2,628)
Power Basis Positions [Member] | Future Years [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Volumes for sales contracts that deliver in future years	(677)
Gas Basis Positions [Member] | 2012 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Gas basis positions (in Bcf)	7.1	[3],[7]
Gas Basis Positions [Member] | 2013 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Gas basis positions (in Bcf)	(5.2)
Gas Basis Positions [Member] | 2014 [Member] | Bcf [Member]
Volumes of Derivative FTR and basis (sales)/purchase contracts [Abstract]
Gas basis positions (in Bcf)	(4.0)
Gas Basis Positions [Member] | Future Years [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Volumes for sales contracts that deliver in future years	(4.0)
Energy Sales Contracts [Member] | 2012 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(10,945)	[3],[8]
Energy Sales Contracts [Member] | 2013 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(6,612)	[8]
Energy Sales Contracts [Member] | 2014 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(3,261)	[8]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2012 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	7,718	[3],[8]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2013 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	2,873	[8]
Related Energy Supply Contracts [Member] | Energy Purchases [Member] | 2014 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	955	[8]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2012 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Volumetric hedge volumes (in units)	73	[3],[8],[9]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2013 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Volumetric hedge volumes (in units)	80	[8],[9]
Related Energy Supply Contracts [Member] | Volumetric Hedges [Member] | 2014 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Volumetric hedge volumes (in units)	65	[8],[9]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2012 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	2,630	[3],[8]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2013 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	3,049	[8]
Related Energy Supply Contracts [Member] | Generation Supply [Member] | 2014 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	2,234	[8]
Retail Gas Sales Contracts [Member] | 2012 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(11.4)	[3]
Retail Gas Sales Contracts [Member] | 2013 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(6.0)
Retail Gas Sales Contracts [Member] | 2014 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(1.8)
Retail Gas Purchase Contracts [Member] | 2012 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	11.2	[3]
Retail Gas Purchase Contracts [Member] | 2013 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	5.8
Retail Gas Purchase Contracts [Member] | 2014 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	1.7
Net Power Sales [Member] | 2012 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(2,076)	[3]
Net Power Sales [Member] | 2013 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(408)
Net Power Sales [Member] | 2014 [Member] | GWh [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	0
Net Fuel Purchases [Member] | 2012 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	16.9	[10],[3]
Net Fuel Purchases [Member] | 2013 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	2.6	[10]
Net Fuel Purchases [Member] | 2014 [Member] | Bcf [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	(0.3)	[10],[11]
Oil Swap [Member] | 2012 [Member] | Boe [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	162,000	[3]
Oil Swap [Member] | 2013 [Member] | Boe [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	285,000
Oil Swap [Member] | 2014 [Member] | Boe [Member]
Notional amounts included under applicable contracts [Abstract]
Notional amount (in units)	240,000

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

[2] 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.

[3] Represents the balance of the current year.

[4] Amount represents derivative (including contracts that qualify for NPNS) 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.

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

[6] Volumes for derivative sales contracts that deliver in future periods total 1,635 GWh and 20.2 Bcf.

[7] Net volumes that deliver in future periods are (677) GWh and (4.0) Bcf.

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

[9] 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.

[10] Included in these volumes are non-options and exercised option contracts that converted to non-option derivative contracts. Volumes associated with option contracts are insignificant.

[11] Volumes for derivative contracts used in support of these strategies that deliver in future periods are insignificant.