Defined Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Pension Plan [Member] | U.S.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	$ 16	$ 17
Interest cost	39	42
Expected return on plan assets	(62)	(57)
Amortization of: [Abstract]
Prior service cost	2	2
Actuarial loss	22	20
Net periodic defined benefit costs (credits) before settlements and special termination benefits	17	24
Special termination benefits	0	2
Net periodic defined benefit costs (credits)	17	26
Pension Plan [Member] | U.K.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	21	19
Interest cost	47	43
Expected return on plan assets	(150)	(125)
Amortization of: [Abstract]
Prior service cost	0	0
Actuarial loss	39	35
Net periodic defined benefit costs (credits) before settlements and special termination benefits	(43)	(28)
Special termination benefits	0	0
Net periodic defined benefit costs (credits)	(43)	(28)
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	1	2
Interest cost	3	6
Expected return on plan assets	(4)	(6)
Amortization of: [Abstract]
Prior service cost	(1)	0
Net periodic defined benefit costs (credits)	(1)	2
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	4	8
LG And E And KU Energy LLC [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	7	7
Interest cost	16	16
Expected return on plan assets	(26)	(22)
Amortization of: [Abstract]
Prior service cost	2	2
Actuarial loss	$ 10	$ 11
Regulatory Asset Amortization Period	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ 4	$ 5
Net periodic defined benefit costs (credits)	9	14
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
Interest cost	2	2
Expected return on plan assets	(2)	(1)
Amortization of: [Abstract]
Net periodic defined benefit costs (credits)	1	2
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	2	3
Louisville Gas And Electric Co [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Interest cost	3	3
Expected return on plan assets	(5)	(5)
Amortization of: [Abstract]
Prior service cost	1	1
Actuarial loss	$ 2	$ 3
Regulatory Asset Amortization Period	15 years	15 years
Deferred recovery of the difference between pension costs calculated with pension accounting policy and pension cost using 15 year amortization period	$ 1	$ 1
Net periodic defined benefit costs (credits)	1	2
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	$ 4