Defined Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Plan [Member] | U.S.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	$ 17	$ 16	$ 49	$ 49
Interest cost	42	44	126	131
Expected return on plan assets	(58)	(57)	(173)	(171)
Amortization of: [Abstract]
Prior service cost	2	2	7	6
Actuarial loss	18	12	52	37
Net periodic defined benefit costs (credits) before settlements and special termination benefits	21	17	61	52
Settlements	7	3	7	3
Special termination benefits	0	0	1	0
Net periodic defined benefit costs (credits)	28	20	69	55
Pension Plan [Member] | U.S. | Nonqualified Plan [Member]
Amortization of: [Abstract]
Settlements	2	3	2	3
Pension Plan [Member] | U.S. | LGE [Member] | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements	5		5
Pension Plan [Member] | U.K.
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	20	17	57	53
Interest cost	45	58	132	182
Expected return on plan assets	(130)	(124)	(382)	(389)
Amortization of: [Abstract]
Prior service cost	0	0	0	0
Actuarial loss	36	34	107	107
Net periodic defined benefit costs (credits) before settlements and special termination benefits	(29)	(15)	(86)	(47)
Settlements	0	0	0	0
Special termination benefits	0	0	0	0
Net periodic defined benefit costs (credits)	(29)	(15)	(86)	(47)
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Employer contributions			485
Other Postretirement Benefits Plan [Member]
Net Periodic Defined Benefit Costs (Credits) (Details) [Abstract]
Service cost	2	2	6	6
Interest cost	5	6	17	19
Expected return on plan assets	(6)	(6)	(17)	(17)
Amortization of: [Abstract]
Prior service cost	0	0	(1)	0
Actuarial loss	1	1	1	1
Net periodic defined benefit costs (credits)	2	3	6	9
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	6	6	19	17
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	17	18	51	53
Expected return on plan assets	(23)	(23)	(69)	(68)
Amortization of: [Abstract]
Prior service cost	2	2	6	6
Actuarial loss	8	5	23	15
Net periodic defined benefit costs before settlements	10	8	29	24
Settlements	$ 5	0	$ 5	$ 0
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	$ 3		$ 8	$ 4
Net periodic defined benefit costs (credits)	15	8	34	24
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	7
Expected return on plan assets	(2)	(2)	(5)	(5)
Amortization of: [Abstract]
Prior service cost	1	1	1	2
Net periodic defined benefit costs (credits)	2	2	5	7
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	3	2	8	7
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	4	9	11
Expected return on plan assets	(5)	(5)	(16)	(15)
Amortization of: [Abstract]
Prior service cost	1	1	3	3
Actuarial loss	3	2	7	5
Net periodic defined benefit costs before settlements	2	2	4	5
Settlements	$ 5	$ 0	$ 5	0
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	$ 1	$ 1	$ 3
Net periodic defined benefit costs (credits)	7	2	9	5
Louisville Gas And Electric Co [Member] | Pension Plan [Member] | Qualified Plan [Member]
Amortization of: [Abstract]
Settlements			5
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	$ 2	$ 2	$ 7	$ 8