Derivative Instruments and Hedging Activities (Fair Values) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair Values by Balance Sheet Location [Abstract]
Asset value	$ 1,098		$ 1,279
Liability value	1,274		1,244
Derivatives Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	12	[1]	91	[1]
Liability value	76	[1]	52	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		82	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		82	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	12	[1]	9	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	6	[1],[2]	9	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	6	[1]	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	28	[1]	20	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	15	[1],[2]	0
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	6	[1],[2]	4	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	7	[1]	16	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0		0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	48	[1]	32	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	7	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	41	[1],[2]	28	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0		4	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0		0
Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1,086	[1]	1,188	[1]
Liability value	1,198	[1]	1,192	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	732	[1]	860	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	19	[1]	0
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	713	[1]	860	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	354	[1]	328	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	26	[1]	0
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	328	[1]	328	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	869	[1]	809	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1],[2]	4	[1],[2]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	15	[1]	55	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	850	[1]	750	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	329	[1]	383	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	38	[1],[2]	32	[1],[2]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0		0
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	31	[1]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	287	[1]	320	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1,041	[1]	1,188	[1]
Liability value	1,137	[1]	1,070	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	713	[1]	860	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	713	[1]	860	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	328	[1]	328	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	328	[1]	328	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	850	[1]	750	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	850	[1]	750	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	287	[1]	320	[1]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	287	[1]	320	[1]
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	6	[1]	0
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	0
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Liability value	42	[1]	36	[1]
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	4	[1]
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	4	[1]
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	38	[1]	32	[1]
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	38	[1]	32	[1]
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	3	[1]	0
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	2	[1]	0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Liability value	42	[1]	36	[1]
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0		0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	4	[1]
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	4	[1]	4	[1]
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	38		32
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	38	[1]	32	[1]
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	3	[1]	0
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	$ 2	[1]	$ 0

[1] Represents the location on the Balance Sheets

[2] Excludes accrued interest, if applicable.