Derivative Instruments and Hedging Activities - Risk Disclosures (Details) £ in Millions, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2018 GBP (£)
Cash Flow Hedges [Member] | Cross Currency Interest Rate Swap Contracts [Member]
Interest Rate Risk - Cash Flow Hedges (Numeric) [Abstract]
Earliest maturity date of cross-currency cash flow hedge contracts			2021
Latest maturity date of cross-currency cash flow hedge contracts			2028
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness	$ 0	$ 0	$ 0	$ 0
Notional amount	702		$ 702
Cash Flow Hedges [Member] | Interest Rate Swap Contracts [Member]
Interest Rate Risk - Cash Flow Hedges (Numeric) [Abstract]
No or insignificant after-tax gains (losses) previously recorded in AOCI reclassified to earnings related to interest rate cash flow hedge contracts			For the three and nine months ended September 30, 2018, PPL had no cash flow hedges reclassified into earnings associated with discontinued cash flow hedges. For the three and nine months ended September 30, 2017, PPL had an insignificant amount of cash flow hedges reclassified into earnings associated with discontinued cash flow hedges.
No or insignificant unrealized after-tax gains (losses) on interest rate cash flow hedge contracts expected to be reclassified into earnings during next 12 months			insignificant
Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness	0	$ 0	$ 0	$ 0
Notional amount	97		$ 97			£ 75
Derivative, Maturity Date			Dec. 31, 2026
Net Investment Hedges [Member] | Combined Foreign Currency Contracts And Intercompany Loans [Member]
Foreign Currency Risk - Net Investment Hedges (Numeric) [Abstract]
Net after tax gains (losses) on net investment hedges recognized in the foreign currency translation adjustment component of AOCI			$ 30		$ 22
Economic Hedges [Member] | Foreign Currency Contracts [Member]
Foreign Currency Risk - Economic Activity (Numeric) [Abstract]
Minimum Termination Date Net Investment Hedges Classified As Economic Activity			Oct. 31, 2018
Maximum Termination Date Net Investment Hedges Classified As Economic Activity			Oct. 31, 2020
Total exposure hedged related to foreign currency contracts for anticipated earnings hedges classified as economic activity	2,500		$ 2,500			£ 1,800
LGE [Member] | Economic Hedges [Member] | Interest Rate Swap Contracts [Member]
Interest Rate Risk - Cash Flow Hedges (Numeric) [Abstract]
Notional amount	147		$ 147
Interest Rate Risk - Economic Activity (Numeric) [Abstract]
Year of expiration of the maximum maturity date of interest rate economic activity contracts			2033
LG And E And KU Energy LLC [Member] | LGE [Member] | Economic Hedges [Member] | Interest Rate Swap Contracts [Member]
Interest Rate Risk - Cash Flow Hedges (Numeric) [Abstract]
Notional amount	147		$ 147
Interest Rate Risk - Economic Activity (Numeric) [Abstract]
Year of expiration of the maximum maturity date of interest rate economic activity contracts			2033
Louisville Gas And Electric Co [Member] | Economic Hedges [Member] | Interest Rate Swap Contracts [Member]
Interest Rate Risk - Cash Flow Hedges (Numeric) [Abstract]
Notional amount	$ 147		$ 147
Interest Rate Risk - Economic Activity (Numeric) [Abstract]
Year of expiration of the maximum maturity date of interest rate economic activity contracts			2033