Defined Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Pension Plan [Member] | U.S.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	$ 15	$ 17	$ 46	$ 49
Interest cost	39	42	117	126
Expected return on plan assets	(62)	(58)	(186)	(173)
Amortization of: [Abstract]
Prior service cost	2	2	7	7
Actuarial loss	22	18	63	52
Net periodic defined benefit costs (credits) before settlements and special termination benefits	16	21	47	61
Settlements	0	1	0	1
Net periodic defined benefit costs (credits)	16	22	47	63
Special termination benefits	0	0	$ 0	1
Collective Bargaining Agreement Term			5 years
Pension Plan [Member] | U.S. | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements	1	5	$ 5	5
Pension Plan [Member] | U.K.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	21	20	63	57
Interest cost	46	45	140	132
Expected return on plan assets	(145)	(130)	(445)	(382)
Amortization of: [Abstract]
Prior service cost	0	0	0	0
Actuarial loss	37	36	114	107
Net periodic defined benefit costs (credits) before settlements and special termination benefits	(41)	(29)	(128)	(86)
Settlements	0	0	0	0
Net periodic defined benefit costs (credits)	(41)	(29)	(128)	(86)
Special termination benefits	0	0	0	0
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	1	2	5	6
Interest cost	5	5	15	17
Expected return on plan assets	(4)	(6)	(17)	(17)
Amortization of: [Abstract]
Prior service cost	0	0	0	(1)
Actuarial loss	0	1	0	1
Net periodic defined benefit costs (credits)	2	2	3	6
PPL Electric Utilities Corp [Member] | PPL Services [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	5	6	12	19
LG And E And KU Energy LLC [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	6	6	18	18
Interest cost	16	17	48	51
Expected return on plan assets	(25)	(23)	(76)	(69)
Amortization of: [Abstract]
Prior service cost	3	2	7	6
Actuarial loss	$ 8	$ 8	$ 26	$ 23
Regulatory Asset Amortization Period	15 years	15 years	15 years	15 years
Net periodic defined benefit costs (credits)	$ 8	$ 10	$ 23	$ 29
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	2	3	8	8
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements	1	5	5	5
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	1	1	3	3
Interest cost	2	2	6	6
Expected return on plan assets	(2)	(2)	(6)	(5)
Amortization of: [Abstract]
Prior service cost	0	1	1	1
Actuarial loss	0	0	(1)	0
Net periodic defined benefit costs (credits)	1	2	3	5
Louisville Gas And Electric Co [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	1	3	5	8
Louisville Gas And Electric Co [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	0	0	1	1
Interest cost	3	3	9	9
Expected return on plan assets	(6)	(5)	(17)	(16)
Amortization of: [Abstract]
Prior service cost	1	1	4	3
Actuarial loss	2	$ 3	$ 5	$ 7
Regulatory Asset Amortization Period		15 years	15 years	15 years
Net periodic defined benefit costs (credits)	0	$ 2	$ 2	$ 4
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period		1	1	3
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements	1	5	$ 5	5
Kentucky Utilities Co [Member]
Amortization of: [Abstract]
Collective Bargaining Agreement Term			3 years
Kentucky Utilities Co [Member] | LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Costs allocated to subsidiary by plan sponsors	$ 1	$ 2	$ 3	$ 7