Derivative Instruments and Hedging Activities (Gains and Losses) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative			$ 0
Gain (loss) recognized in income on related item			3
Cash Flow Hedges [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	85	163	712
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	2	1	(3)
Cash Flow Hedges [Member] | Other Comprehensive Income [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	(33)	86	71
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Other Comprehensive Income [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	(91)	127	(28)
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	(18)	(20)	(18)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	2	0	0
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)			1
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)			0
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Other Comprehensive Income [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	58	(41)	(15)
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	4	1	(2)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	57	(28)	(23)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Other Comprehensive Income [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	0	0	114
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Depreciation [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	2	2	2
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	31	(58)	(136)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	(2)
Cash Flow Hedges [Member] | Commodity Contracts [Member] | Other Operation And Maintenance [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)		3
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)		0
Net Investment Hedges [Member] | Foreign Currency Contracts [Member] | Other Comprehensive Income [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	23	(14)	(7)
Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(66)	0	0
Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Liabilities Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	0	72	14
Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Unregulated Wholesale Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	1	240	838
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	1	(1)
Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Discontinued Operations [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	8	23	50
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
Derivatives Not Designated As Hedging Instruments [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(221)	26	204
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(12)	22	1
Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(8)	(8)	(8)
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Unregulated Wholesale Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(1,353)	(99)	1,182
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Fuel [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(30)	2	0
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	1,013	130	(965)
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Unregulated Retail Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	30	25	30
Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Discontinued Operations [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	6	14	17
Derivatives Not Designated As Hedging Instruments [Member] | Foreign Currency Contracts [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	121	(38)	(52)
PPL Energy Supply LLC [Member] | Cash Flow Hedges [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	0	0	114
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	42	207	754
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	1	(3)
PPL Energy Supply LLC [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in OCI on derivative (effective portion)	0	0	114
PPL Energy Supply LLC [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Depreciation [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	2	2	2
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
PPL Energy Supply LLC [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	31	(58)	(136)
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	(2)
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Unregulated Wholesale Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	1	240	838
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	1	(1)
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Commodity Contracts [Member] | Discontinued Operations [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) reclassified from AOCI into income on derivative (effective portion)	8	23	50
Gain (loss) recognized in income on derivative (ineffective portion and amount excluded from effectiveness testing)	0	0	0
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(334)	72	264
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Unregulated Wholesale Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(1,353)	(99)	1,182
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Fuel [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(30)	2	0
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Energy Purchases [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	1,013	130	(965)
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Unregulated Retail Energy [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	30	25	30
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Commodity Contracts [Member] | Discontinued Operations [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	6	14	17
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gains (losses) recognized as regulatory asset on derivative	(66)	0	0
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Liabilities Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	0	72	14
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(12)	22	1
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(8)	(8)	(8)
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gains (losses) recognized as regulatory asset on derivative	(33)	0	0
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Liabilities Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	0	36	7
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(12)	22	1
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	(8)	(8)	(8)
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Assets Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gains (losses) recognized as regulatory asset on derivative	(33)	0	0
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Regulatory Liabilities Noncurrent [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized as regulatory liabilities/assets	$ 0	$ 36	$ 7