Defined Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Collective Bargaining Agreement Term			5 years
Pension Plan [Member] | U.S.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	$ 15	$ 15	$ 31	$ 32
Interest cost	39	42	78	84
Expected return on plan assets	(62)	(58)	(124)	(115)
Amortization of: [Abstract]
Prior service cost	3	3	5	5
Actuarial loss	19	14	41	34
Net periodic defined benefit costs (credits) before special termination benefits	14	16	31	40
Special termination benefits	0	(1)	0	1
Net periodic defined benefit costs (credits)	14	15	31	41
Pension Plan [Member] | U.K.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	21	18	42	37
Interest cost	47	44	94	87
Expected return on plan assets	(150)	(127)	(300)	(252)
Amortization of: [Abstract]
Prior service cost	0	0	0	0
Actuarial loss	38	36	77	71
Net periodic defined benefit costs (credits) before special termination benefits	(44)	(29)	(87)	(57)
Special termination benefits	0	0	0	0
Net periodic defined benefit costs (credits)	(44)	(29)	(87)	(57)
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	3	2	4	4
Interest cost	7	6	10	12
Expected return on plan assets	(9)	(5)	(13)	(11)
Amortization of: [Abstract]
Prior service cost	1	(1)	0	(1)
Net periodic defined benefit costs (credits)	2	2	1	4
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	3	5	7	13
LG And E And KU Energy LLC [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	5	5	12	12
Interest cost	16	18	32	34
Expected return on plan assets	(25)	(24)	(51)	(46)
Amortization of: [Abstract]
Prior service cost	2	2	4	4
Actuarial loss	$ 8	4	$ 18	$ 15
Regulatory Asset Amortization Period	15 years		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	$ 2		$ 6	$ 5
Net periodic defined benefit costs (credits)	6	5	15	19
LG And E And KU Energy LLC [Member] | Pension Plan [Member] | U.S. | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements			4
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	2	2
Interest cost	2	2	4	4
Expected return on plan assets	(2)	(2)	(4)	(3)
Amortization of: [Abstract]
Prior service cost	1	0	1	0
Actuarial loss	(1)	0	(1)	0
Net periodic defined benefit costs (credits)	1	1	2	3
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	2	4	5
Louisville Gas And Electric Co [Member] | Pension Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	1	1	1	1
Interest cost	3	3	6	6
Expected return on plan assets	(6)	(6)	(11)	(11)
Amortization of: [Abstract]
Prior service cost	2	1	3	2
Actuarial loss	1	1	$ 3	$ 4
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	0	2	2
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | U.S. | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements			$ 4
Kentucky Utilities Co [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [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	$ 1	$ 2	$ 5