Derivative Instruments and Hedging Activities (Fair Values) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012	Dec. 31, 2011
Fair Values by Balance Sheet Location [Abstract]
Asset value	$ 1,595		$ 2,097
Liability value	1,361		1,694
Net pre-tax gains (losses) included in AOCI related to derivatives not designated as hedging instruments	216		300
Accumulated after-tax net gains (losses), excluding net investment hedges, included in AOCI	87		132		231	527
Derivatives Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	114	[1]	115	[1]
Liability value	29	[1]	28	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	84	[1]	73	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	83	[1],[2]	14	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			59	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	30	[1]	42	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	3	[1],[2]	1	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	27	[1]	14	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			27	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	22	[1]	27	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	16	[1],[2]	22	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	1	[1]	3	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	5	[1]	2	[1]
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	7	[1]	1	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	1	[1],[2]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value			1	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	6	[1]
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1,481	[1],[3]	1,982	[1],[3]
Liability value	1,332	[1],[3]	1,666	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	961	[1],[3]	1,452	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	961	[1],[3]	1,452	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	520	[1],[3]	530	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	519	[1],[3]	530	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	801	[1],[3]	1,038	[1],[3]
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],[3]	5	[1],[2],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	24	[1],[3]	23	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	773	[1],[3]	1,010	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	531	[1],[3]	628	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	37	[1],[2],[3]	53	[1],[2],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Cross Currency Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Foreign Currency Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	32	[1],[3]	19	[1],[3]
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	462	[1],[3]	556	[1],[3]
PPL Energy Supply LLC [Member]
Fair Values by Balance Sheet Location [Abstract]
Net pre-tax gains (losses) included in AOCI related to derivatives not designated as hedging instruments	216		300
Accumulated after-tax net gains (losses), excluding net investment hedges, included in AOCI	115		211		312	605
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			86	[1]
Liability value
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			59	[1]
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			59	[1]
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			27	[1]
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			27	[1]
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
PPL Energy Supply LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1,480	[1],[3]	1,982	[1],[3]
Liability value	1,235	[1],[3]	1,566	[1],[3]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	961	[1],[3]	1,452	[1],[3]
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	961	[1],[3]	1,452	[1],[3]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	519	[1],[3]	530	[1],[3]
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	519	[1],[3]	530	[1],[3]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	773	[1],[3]	1,010	[1],[3]
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	773	[1],[3]	1,010	[1],[3]
PPL Energy Supply LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	462	[1],[3]	556	[1],[3]
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	462	[1],[3]	556	[1],[3]
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			14	[1]
LG And E And KU Energy LLC [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	14	[1]
LG And E And KU Energy LLC [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Liability value	41	[1]	58	[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
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
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
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
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]	5	[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]	5	[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	37	[1]	53	[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	37	[1]	53	[1]
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			7	[1]
Louisville Gas And Electric Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	7	[1]
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value
Liability value	41	[1]	58	[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
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
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
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
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]	5	[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]	5	[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	37	[1]	53	[1]
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	37	[1]	53	[1]
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value			7	[1]
Kentucky Utilities Co [Member] | Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	$ 7	[1]

[1] Represents the location on the Balance Sheets.

[2] Excludes accrued interest, if applicable.

[3] $216 million and $300 million of net gains associated with derivatives that were no longer designated as hedging instruments are recorded in AOCI at September 30, 2013 and December 31, 2012.