Derivative Instruments and Hedging Activities (Gains and Losses) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments Gain Loss [Line Items]
Interest Expense	$ 1,001	$ 994	$ 963
Other Income (Expense) - net	169	309	396
Cash Flow Hedges [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Reclassified from AOCI into Income	(32)	(18)	35
Cash Flow Hedges [Member] | Other Comprehensive Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Gain (Loss) Recognized in OCI	(24)	(13)	45
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Other Comprehensive Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Gain (Loss) Recognized in OCI	(9)	(30)	4
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Other Income (Expense) Net [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Amount of gain (loss) reclassified from AOCI to income	0	0
Cash Flow Hedges [Member] | Interest Rate Swaps [Member] | Interest Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Reclassified from AOCI into Income	(10)	(9)	(8)
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Amount of gain (loss) reclassified from AOCI to income	(10)	(9)
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Other Comprehensive Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Gain (Loss) Recognized in OCI	(15)	17	41
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Other Income (Expense) Net [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Reclassified from AOCI into Income	(22)	(9)	42
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Amount of gain (loss) reclassified from AOCI to income	(22)	(9)
Hedged Items	22	9
Cash Flow Hedges [Member] | Cross Currency Swaps [Member] | Interest Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Gain (Loss) Reclassified from AOCI into Income			1
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Amount of gain (loss) reclassified from AOCI to income	0	0
Hedged Items	0	0
Net Investment Hedges [Member] | Foreign Currency Contracts [Member] | Other Comprehensive Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Gain (Loss) Recognized in OCI	1	2	11
Derivatives Not Designated As Hedging Instruments [Member]
Amounts Included in Income, OCI or Regulatory Liabilities/Assets [Abstract]
Gain (loss) recognized in income on derivative	(103)	(19)	145
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	(2)	(1)	6
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	(5)	(5)	(5)
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	(98)	(14)	150
LG And E And KU Energy LLC [Member]
Derivative Instruments Gain Loss [Line Items]
Interest Expense	223	226	206
Other Income (Expense) - net	2	(13)	(16)
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	(2)	(1)	6
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 in income on derivative	(5)	(5)	(5)
Louisville Gas And Electric Co [Member]
Derivative Instruments Gain Loss [Line Items]
Interest Expense	87	87	76
Other Income (Expense) - net	(1)	(11)	(12)
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	(2)	(1)	6
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 in income on derivative	(5)	(5)	(5)
Kentucky Utilities Co [Member]
Derivative Instruments Gain Loss [Line Items]
Interest Expense	113	109	100
Other Income (Expense) - net	$ 3	$ (4)	$ (6)