Utility Rate Regulation (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 MW Integer		Dec. 31, 2011
Regulatory Assets [Line Items]
Current regulatory assets	$ 17		$ 9
Noncurrent regulatory assets	1,335		1,349
Regulatory Liabilities [Line Items]
Current regulatory liabilities	58		73
Noncurrent regulatory liabilities	1,003		1,010
Regulatory Matters - Kentucky Activities - Certificate of Public Convenience and Necessity Filing (Numeric) [Abstract]
Capacity of proposed NGCC (in MW)	640
LG&E undivided ownership interest in proposed combined cycle turbine	22.00%
KU undivided ownership interest in proposed combined cycle turbine	78.00%
Generating units anticipated to be retired at the Cane Run plant	3
Generating units anticipated to be retired at the Tyrone plant	1
Generating units anticipated to be retired at the Green River plant	2
Capacity of coal-fired generation units that the company anticipates retiring in 2015 (in MW)	797
Regulatory Matters - Kentucky Activities - Kentucky Acquisition Commitments (Numeric) [Abstract]
Rate of return on common equity if exceeded triggers costs savings being returned to customers	10.75%
Percentage of excess return on equity amount that ultimately will be returned to customers	50.00%
Regulatory Matters - Pennsylvania Activities - PUC Investigation of Retail Market (Numeric) [Abstract]
Number of phases of a PUC investigation of retail electricity market	2
Number of possible models for the default service end state	3
Regulatory Matters - Pennsylvania Activities - Legislation - Regulatory Procedures and Mechanisms (Numeric) [Abstract]
Number of ratemaking mechanisms authorized for PUC approval	2
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Under Act 129, percentage reduction in electricity consumption by 2011	1.00%
Under Act 129, percentage reduction in electricity consumption by 2013	3.00%
Under Act 129, percentage reduction in peak demand electricity consumption by 2013	4.50%
Number of hours that are the benchmark for demand reductions by 2013	100
Under Act 129, percentage cap on costs that can be recovered for implementation of EE and C plan	2.00%
Number of years EDCs have to comply with consumption reduction target	3
Under Act 129, percentage reduction in electricity target for the company under the Phase II program	2.10%
Minimum term of long term supply contract under Act 129 (in years)	4
Maximum term of long term supply contract under Act 129 (in years)	20
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%
Regulatory Matters - Federal Matters - FERC Formula Rates (Numeric) [Abstract]
Review and challenge period for 2012 Annual Update (in days)	180
Requested recovery period (in years)	34
Regulatory asset amount recorded related to certain deferred state tax assets	50		50
Regulatory Matters - U.K. Activities - Ofgem Review of Line Loss Calculation (Numeric) [Abstract]
WPD's projected cost for compliance with overhead electricity standards	167		170
Number of potential changes cited in a consultation paper issued by Ofgem	2
PPL Electric [Member]
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.25%
PPL Electric [Member] | Distribution Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	105
Percentage increase (decrease) to rates	2.90%
LGE [Member]
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
LGE [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	62
Percentage increase (decrease) to rates	6.90%
LGE [Member] | Gas Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	17
Percentage increase (decrease) to rates	7.00%
KU [Member]
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
KU [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	82
Percentage increase (decrease) to rates	6.50%
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	21		42
Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9		7
Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5		6
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4		2
Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7		0
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7		0
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	666		651
Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	161	[1]	180	[1]
Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	112	[1]	116	[1]
Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	37		39
Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	9		7
Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	10		9
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5		16
Noncurrent regulatory liabilities	8		8
Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7		6
Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10		3
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	595		615
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	297		289
Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	148		154
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	103		110
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	71		69
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	62		53
Coal Contracts [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	7	[1]	11	[1]
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	23		18
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	29		30
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	734		729
Regulatory Liabilities [Line Items]
Current regulatory liabilities	42		53
Noncurrent regulatory liabilities	9		7
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.25%
Regulatory Matters - Pennsylvania Activities - PUC Investigation of Retail Market (Numeric) [Abstract]
Number of phases of a PUC investigation of retail electricity market	2
Number of possible models for the default service end state	3
Regulatory Matters - Pennsylvania Activities - Legislation - Regulatory Procedures and Mechanisms (Numeric) [Abstract]
Number of ratemaking mechanisms authorized for PUC approval	2
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Under Act 129, percentage reduction in electricity consumption by 2011	1.00%
Under Act 129, percentage reduction in electricity consumption by 2013	3.00%
Under Act 129, percentage reduction in peak demand electricity consumption by 2013	4.50%
Number of hours that are the benchmark for demand reductions by 2013	100
Under Act 129, percentage cap on costs that can be recovered for implementation of EE and C plan	2.00%
Number of years EDCs have to comply with consumption reduction target	3
Under Act 129, percentage reduction in electricity target for the company under the Phase II program	2.10%
Minimum term of long term supply contract under Act 129 (in years)	4
Maximum term of long term supply contract under Act 129 (in years)	20
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%
Regulatory Matters - Federal Matters - FERC Formula Rates (Numeric) [Abstract]
Review and challenge period for 2012 Annual Update (in days)	180
Requested recovery period (in years)	34
Regulatory asset amount recorded related to certain deferred state tax assets	50		50
PPL Electric Utilities Corp [Member] | Distribution Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	105
Percentage increase (decrease) to rates	2.90%
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	21		42
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4		2
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7		0
PPL Electric Utilities Corp [Member] | Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7		0
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	9		7
PPL Electric Utilities Corp [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3		9
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	270		276
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	297		289
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	32		31
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	71		77
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	62		53
PPL Electric Utilities Corp [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	2		3
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	17		9
Noncurrent regulatory assets	601		620
Regulatory Liabilities [Line Items]
Current regulatory liabilities	16		20
Noncurrent regulatory liabilities	994		1,003
Regulatory Matters - Kentucky Activities - Certificate of Public Convenience and Necessity Filing (Numeric) [Abstract]
Capacity of proposed NGCC (in MW)	640
LG&E undivided ownership interest in proposed combined cycle turbine	22.00%
KU undivided ownership interest in proposed combined cycle turbine	78.00%
Generating units anticipated to be retired at the Cane Run plant	3
Generating units anticipated to be retired at the Tyrone plant	1
Generating units anticipated to be retired at the Green River plant	2
Capacity of coal-fired generation units that the company anticipates retiring in 2015 (in MW)	797
Regulatory Matters - Kentucky Activities - Kentucky Acquisition Commitments (Numeric) [Abstract]
Rate of return on common equity if exceeded triggers costs savings being returned to customers	10.75%
Percentage of excess return on equity amount that ultimately will be returned to customers	50.00%
LG And E And KU Energy LLC [Member] | LGE [Member]
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
LG And E And KU Energy LLC [Member] | LGE [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	62
Percentage increase (decrease) to rates	6.90%
LG And E And KU Energy LLC [Member] | LGE [Member] | Gas Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	17
Percentage increase (decrease) to rates	7.00%
LG And E And KU Energy LLC [Member] | KU [Member]
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
LG And E And KU Energy LLC [Member] | KU [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	82
Percentage increase (decrease) to rates	6.50%
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9		7
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5		6
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	666		651
LG And E And KU Energy LLC [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	161	[1]	180	[1]
LG And E And KU Energy LLC [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	112	[1]	116	[1]
LG And E And KU Energy LLC [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	37		39
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	10		9
LG And E And KU Energy LLC [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2		7
Noncurrent regulatory liabilities	8		8
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7		6
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10		3
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	325		339
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	116		123
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	32		33
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	71		69
LG And E And KU Energy LLC [Member] | Coal Contracts [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	7	[1]	11	[1]
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	23		18
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	27		27
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	13		9
Noncurrent regulatory assets	391		403
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7		10
Noncurrent regulatory liabilities	472		478
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
Regulatory Matters - Kentucky Activities - Certificate of Public Convenience and Necessity Filing (Numeric) [Abstract]
Capacity of proposed NGCC (in MW)	640
LG&E undivided ownership interest in proposed combined cycle turbine	22.00%
Generating units anticipated to be retired at the Cane Run plant	3
Capacity of coal-fired generation units that the company anticipates retiring in 2015 (in MW)	797
Regulatory Matters - Kentucky Activities - Kentucky Acquisition Commitments (Numeric) [Abstract]
Rate of return on common equity if exceeded triggers costs savings being returned to customers	10.75%
Percentage of excess return on equity amount that ultimately will be returned to customers	50.00%
Louisville Gas And Electric Co [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	62
Percentage increase (decrease) to rates	6.90%
Louisville Gas And Electric Co [Member] | Gas Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	17
Percentage increase (decrease) to rates	7.00%
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5		6
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	291		286
Louisville Gas And Electric Co [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	70	[1]	78	[1]
Louisville Gas And Electric Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	78	[1]	80	[1]
Louisville Gas And Electric Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	30		31
Louisville Gas And Electric Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2		4
Noncurrent regulatory liabilities	3		3
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7		6
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6		3
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	215		225
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	63		66
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	21		21
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	71		69
Louisville Gas And Electric Co [Member] | Coal Contracts [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3	[1]	5	[1]
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	12		11
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	6		6
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4		0
Noncurrent regulatory assets	210		217
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9		10
Noncurrent regulatory liabilities	522		525
Rate Case Proceeding (Numeric) [Abstract]
Return on equity request included in rate case	11.00%
Regulatory Matters - Kentucky Activities - Certificate of Public Convenience and Necessity Filing (Numeric) [Abstract]
Capacity of proposed NGCC (in MW)	640
KU undivided ownership interest in proposed combined cycle turbine	78.00%
Generating units anticipated to be retired at the Tyrone plant	1
Generating units anticipated to be retired at the Green River plant	2
Capacity of coal-fired generation units that the company anticipates retiring in 2015 (in MW)	797
Regulatory Matters - Kentucky Activities - Kentucky Acquisition Commitments (Numeric) [Abstract]
Rate of return on common equity if exceeded triggers costs savings being returned to customers	10.75%
Percentage of excess return on equity amount that ultimately will be returned to customers	50.00%
Kentucky Utilities Co [Member] | Electric Rates [Member]
Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of requested increase (decrease) to rates	82
Percentage increase (decrease) to rates	6.50%
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9		7
Kentucky Utilities Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	375		365
Kentucky Utilities Co [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	91	[1]	102	[1]
Kentucky Utilities Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	34	[1]	36	[1]
Kentucky Utilities Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	7		8
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	10		9
Kentucky Utilities Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0		3
Noncurrent regulatory liabilities	5		5
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4		0
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	110		114
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	53		57
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	11		12
Kentucky Utilities Co [Member] | Coal Contracts [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	4	[1]	6	[1]
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	11		7
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	$ 21		$ 21

[1] These regulatory assets and liabilities were recorded as offsets to certain intangible assets and liabilities that were recorded at fair value upon the acquisition of LKE.