Utility Rate Regulation (Regulatory Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Regulatory Assets and Liabilities - Act 129 Compliance Rider (Numeric) [Abstract]
Maximum recoverable cost	250
Defined Benefit Plans [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2015
Regulatory Assets and Liabilities - Defined Benefit Plans (Numeric) [Abstract]
Regulatory asset costs expected to be amortized into net periodic defined benefit costs in the next year	58
Unamortized Loss On Debt [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2040
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	five-year
Act 129 Compliance Rider [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	three-year
Amortization end date	May 31, 2016
Regulatory Assets and Liabilities - Act 129 Compliance Rider (Numeric) [Abstract]
Maximum recoverable cost Phase II	185
Environmental Cost Recovery [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Regulatory Assets and Liabilities - Environmental Cost Recovery (Numeric) [Abstract]
Return on equity for approved projects remaining from earlier ECR plans		10.25%
Return on equity for approved projects in the 2009 ECR proceedings			10.63%
Return on equity for approved projects in the 2011 ECR proceedings	10.10%
Gas Supply Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 18 months
Fuel Adjustment Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Interest Rate Swaps [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date		Dec. 31, 2033
Regulatory Assets and Liabilities - Interest Rate Swaps (Numeric) [Abstract]
Principal amount of debt related to interest rate swap that is receiving regulatory accounting treatment	1,000
Realized gains (losses) recognized during period that is receiving regulatory accounting treatment		86
Amortization end date for 2008 terminated swap contract		Dec. 31, 2035
Gas Line Tracker [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Return on equity			10.25%
Regulatory Assets and Liabilities - Gas Line Tracker (Numeric) [Abstract]
Term, in years, of the gas service rider program			5
Coal Contracts [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2016
Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Mar. 31, 2026
PPL Electric Utilities Corp [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Return on equity			10.40%
Regulatory Assets and Liabilities - Act 129 Compliance Rider (Numeric) [Abstract]
Maximum recoverable cost	250
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2015
Regulatory Assets and Liabilities - Defined Benefit Plans (Numeric) [Abstract]
Regulatory asset costs expected to be amortized into net periodic defined benefit costs in the next year	18
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	three years
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2029
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	five-year
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	three-year
Amortization end date	May 31, 2016
Regulatory Assets and Liabilities - Act 129 Compliance Rider (Numeric) [Abstract]
Maximum recoverable cost Phase II	185
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2015
Regulatory Assets and Liabilities - Defined Benefit Plans (Numeric) [Abstract]
Regulatory asset costs expected to be amortized into net periodic defined benefit costs in the next year	40
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2020
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2040
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Regulatory Assets and Liabilities - Environmental Cost Recovery (Numeric) [Abstract]
Return on equity for approved projects remaining from earlier ECR plans		10.25%
Return on equity for approved projects in the 2009 ECR proceedings			10.63%
Return on equity for approved projects in the 2011 ECR proceedings	10.10%
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 18 months
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date		Dec. 31, 2033
Regulatory Assets and Liabilities - Interest Rate Swaps (Numeric) [Abstract]
Principal amount of debt related to interest rate swap that is receiving regulatory accounting treatment	1,000
Realized gains (losses) recognized during period that is receiving regulatory accounting treatment		86
Amortization end date for 2008 terminated swap contract		Dec. 31, 2035
LG And E And KU Energy LLC [Member] | Gas Line Tracker [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Return on equity			10.25%
Regulatory Assets and Liabilities - Gas Line Tracker (Numeric) [Abstract]
Term, in years, of the gas service rider program			5
LG And E And KU Energy LLC [Member] | Coal Contracts [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2016
LG And E And KU Energy LLC [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Mar. 31, 2026
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2015
Regulatory Assets and Liabilities - Defined Benefit Plans (Numeric) [Abstract]
Regulatory asset costs expected to be amortized into net periodic defined benefit costs in the next year	25
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2020
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2035
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Regulatory Assets and Liabilities - Environmental Cost Recovery (Numeric) [Abstract]
Return on equity for approved projects remaining from earlier ECR plans		10.25%
Return on equity for approved projects in the 2009 ECR proceedings			10.63%
Return on equity for approved projects in the 2011 ECR proceedings	10.10%
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 18 months
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date		Dec. 31, 2033
Regulatory Assets and Liabilities - Interest Rate Swaps (Numeric) [Abstract]
Principal amount of debt related to interest rate swap that is receiving regulatory accounting treatment	500
Realized gains (losses) recognized during period that is receiving regulatory accounting treatment		43
Amortization end date for 2008 terminated swap contract		Dec. 31, 2035
Louisville Gas And Electric Co [Member] | Gas Line Tracker [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Return on equity			10.25%
Regulatory Assets and Liabilities - Gas Line Tracker (Numeric) [Abstract]
Term, in years, of the gas service rider program			5
Louisville Gas And Electric Co [Member] | Coal Contracts [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2016
Louisville Gas And Electric Co [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Mar. 31, 2026
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2015
Regulatory Assets and Liabilities - Defined Benefit Plans (Numeric) [Abstract]
Regulatory asset costs expected to be amortized into net periodic defined benefit costs in the next year	15
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2020
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2040
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Regulatory Assets and Liabilities - Environmental Cost Recovery (Numeric) [Abstract]
Return on equity for approved projects remaining from earlier ECR plans		10.25%
Return on equity for approved projects in the 2009 ECR proceedings			10.63%
Return on equity for approved projects in the 2011 ECR proceedings	10.10%
Kentucky Utilities Co [Member] | Gas Supply Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 18 months
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization period	within 12 months
Period of recurring reviews of activity	six-month
Period of when rider amounts are rolled into base rates	two-year
Kentucky Utilities Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets and Liabilities - Interest Rate Swaps (Numeric) [Abstract]
Principal amount of debt related to interest rate swap that is receiving regulatory accounting treatment	500
Realized gains (losses) recognized during period that is receiving regulatory accounting treatment		43
Kentucky Utilities Co [Member] | Coal Contracts [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Dec. 31, 2016
Kentucky Utilities Co [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Assets and Liabilities (Numeric) [Line Items]
Amortization end date	Mar. 31, 2026