Related Party Transactions (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Oct. 31, 2018
PPL Electric Utilities Corp [Member] | PPL Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		$ 14	$ 43	$ 45	$ 138
PPL Electric Utilities Corp [Member] | PPL EU Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		34	15	110	48
PPL Electric Utilities Corp [Member] | PPL Energy Funding [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		650		650
Notes receivable from affiliate		0		0		$ 0
Intercompany Note Affiliate Maximum Borrowing Capacity Increase		250		250
LG And E And KU Energy LLC [Member]
Intercompany Borrowings (Numeric) [Abstract]
Notes payable to affiliates		80		80		225
Long-term debt to affiliate		650		650		400
Interest Expense with Affiliate		7	5	18	13
LG And E And KU Energy LLC [Member] | PPL Services [Member]
Support Costs (Details) [Abstract]
Support cost allocations from subsidiary of parent to registrant		5	4	19	15
LG And E And KU Energy LLC [Member] | PPL Energy Funding [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		300		300
Notes payable to affiliates		80		$ 80		$ 225
Intercompany borrowings demand note rate on outstanding borrowing				3.61%		2.87%
LG And E And KU Energy LLC [Member] | PPL Energy Funding [Member] | Subsequent Event [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity							$ 375
Intercompany Note Affiliate Maximum Borrowing Capacity Increase							$ 75
LG And E And KU Energy LLC [Member] | PPL Affiliate [Member]
Intercompany Borrowings (Numeric) [Abstract]
Intercompany note with affiliate maximum borrowing capacity		300		$ 300
Notes Receivable, Related Parties, Noncurrent		0		$ 0		$ 0
LG And E And KU Energy LLC [Member] | PPL Affiliate [Member]
Intercompany Borrowings (Numeric) [Abstract]
Debt instrument term (in years)				10 years
Long-term debt to affiliate		$ 400		$ 400
Interest rate on ten-year note		3.50%		3.50%
Interest Expense with Affiliate		$ 4	4	$ 11	11
LG And E And KU Energy LLC [Member] | Affiliated Entity [Member]
Intercompany Borrowings (Numeric) [Abstract]
Interest Expense with Affiliate		3		4
LG And E And KU Energy LLC [Member] | Note Payable [Member] | Affiliated Entity [Member]
Intercompany Borrowings (Numeric) [Abstract]
Stated interest rate	4.00%
Maturity date	May 31, 2028
Notes Payable, Noncurrent	$ 250
Louisville Gas And Electric Co [Member] | LKS [Member]
Intercompany Billings by LKS (Details) [Abstract]
Intercompany billings between affiliates		36	38	113	120
Kentucky Utilities Co [Member] | LKS [Member]
Intercompany Billings by LKS (Details) [Abstract]
Intercompany billings between affiliates		$ 42	$ 43	$ 127	$ 134