Derivative Instruments and Hedging Activities (Gains and Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Credit Risk-Related Contingent Features [Abstract]
Aggregate fair value of derivative instruments in a net liability position with credit contingent provisions	211
Aggregate fair value of collateral posted on these derivative instruments	53
Aggregate fair value of additional collateral requirements in the event of a credit downgrade below investment grade	175	[1]
Fair Value Hedges [Member] | Interest Rate Swaps [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Hedged items in fair value hedging relationships	Fixed rate debt		Fixed rate debt
Fair Value Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	0		1
Gain (loss) recognized in income on related item	1		10
Cash Flow Hedges [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	128		69
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	209		120
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0		(9)
Cash Flow Hedges [Member] | Interest Rate Swaps [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	3		10
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	(4)		(3)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0		(1)
Cash Flow Hedges [Member] | Cross Currency Swaps [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	12		(25)
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	(1)		3
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0		0
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	(19)		(13)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0		0
Cash Flow Hedges [Member] | Commodity Contracts [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	113		84
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Wholesale Energy Marketing [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	272		203
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	4		(9)
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Depreciation [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	1		0
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0		0
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	(40)		(70)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	(4)		1
Derivatives Not Designated As Hedging Instruments [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	290		10
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Regulatory Assets [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gains (losses) recognized as regulatory asset on derivative	7		2
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	(2)		(2)
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Wholesale Energy Marketing [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	1,343		45
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Fuel [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	6		23
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	(1,070)		(55)
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Unregulated Retail Electric And Gas [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	22		1
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Net Energy Trading Margins [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	9	[2]	7	[2]
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Currency Contracts [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in income on derivative	(18)		(9)
Net Investment Hedges [Member] | Foreign Currency Contracts [Member]
Amounts Included in Income, OCI or Regulatory Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	(3)		(1)

[1] Includes the effect of net receivables and payables already recorded on the Balance Sheet.

[2] Differs from the Statement of Income due to intra-month transactions that PPL defines as spot activity, which is not accounted for as a derivative.