Derivative Instruments and Hedging Activities (Offseting Derivative Instruments and Credit Risk-Related Features) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Offsetting Assets And Liabilities [Line Items]
Gross assets	$ 1,098		$ 1,279
Derivative instruments eligible for offset - assets	961		973
Cash collateral received eligible for offset - assets	9		7
Net assets	128		299
Gross liabilities	1,274		1,244
Derivative instruments eligible for offset - liabilities	961		973
Cash collateral pledged eligible for offset - liabilities	123		24
Net liabilities	190		247
Credit Risk-Related Contingent Features [Abstract]
Aggregate fair value of derivative instruments in a net liability position with credit risk-related contingent features	179
Aggregate fair value of collateral posted on these derivative instruments	119
Aggregate fair value of additional collateral requirements in the event of a credit downgrade below investment grade	91	[1],[2]
Energy Commodities [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	1,041		1,188
Derivative instruments eligible for offset - assets	915		912
Cash collateral received eligible for offset - assets	9		7
Net assets	117		269
Gross liabilities	1,137		1,070
Derivative instruments eligible for offset - liabilities	915		912
Cash collateral pledged eligible for offset - liabilities	102		1
Net liabilities	120		157
Treasury Derivatives [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	57		91
Derivative instruments eligible for offset - assets	46		61
Cash collateral received eligible for offset - assets	0		0
Net assets	11		30
Gross liabilities	137		174
Derivative instruments eligible for offset - liabilities	46		61
Cash collateral pledged eligible for offset - liabilities	21		23
Net liabilities	70		90
PPL Energy Supply LLC [Member]
Credit Risk-Related Contingent Features [Abstract]
Aggregate fair value of derivative instruments in a net liability position with credit risk-related contingent features	118
Aggregate fair value of collateral posted on these derivative instruments	99
Aggregate fair value of additional collateral requirements in the event of a credit downgrade below investment grade	49	[1],[2]
PPL Energy Supply LLC [Member] | Energy Commodities [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	1,041		1,188
Derivative instruments eligible for offset - assets	915		912
Cash collateral received eligible for offset - assets	9		7
Net assets	117		269
Gross liabilities	1,137		1,070
Derivative instruments eligible for offset - liabilities	915		912
Cash collateral pledged eligible for offset - liabilities	102		1
Net liabilities	120		157
LG And E And KU Energy LLC [Member]
Credit Risk-Related Contingent Features [Abstract]
Aggregate fair value of derivative instruments in a net liability position with credit risk-related contingent features	27
Aggregate fair value of collateral posted on these derivative instruments	20
Aggregate fair value of additional collateral requirements in the event of a credit downgrade below investment grade	8	[1]
LG And E And KU Energy LLC [Member] | Treasury Derivatives [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	6		0
Derivative instruments eligible for offset - assets	4		0
Cash collateral received eligible for offset - assets	0		0
Net assets	2		0
Gross liabilities	46		36
Derivative instruments eligible for offset - liabilities	4		0
Cash collateral pledged eligible for offset - liabilities	19		20
Net liabilities	23		16
Louisville Gas And Electric Co [Member]
Credit Risk-Related Contingent Features [Abstract]
Aggregate fair value of derivative instruments in a net liability position with credit risk-related contingent features	27
Aggregate fair value of collateral posted on these derivative instruments	20
Aggregate fair value of additional collateral requirements in the event of a credit downgrade below investment grade	8	[1]
Louisville Gas And Electric Co [Member] | Treasury Derivatives [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	3		0
Derivative instruments eligible for offset - assets	2		0
Cash collateral received eligible for offset - assets	0		0
Net assets	1		0
Gross liabilities	44		36
Derivative instruments eligible for offset - liabilities	2		0
Cash collateral pledged eligible for offset - liabilities	19		20
Net liabilities	23		16
Kentucky Utilities Co [Member] | Treasury Derivatives [Member]
Offsetting Assets And Liabilities [Line Items]
Gross assets	3
Derivative instruments eligible for offset - assets	2
Cash collateral received eligible for offset - assets	0
Net assets	1
Gross liabilities	2
Derivative instruments eligible for offset - liabilities	2
Cash collateral pledged eligible for offset - liabilities	0
Net liabilities	$ 0

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

[2] During the second quarter of 2014, PPL Energy Supply experienced a downgrade in its corporate credit ratings to below investment grade. Amounts related to PPL Energy Supply represent net liability positions subject to further adequate assurance features.