Defined Benefits (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Subsequent Event [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Payment for Pension Benefits	$ 23
Pension Plan [Member] | U.S.
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		$ 14	$ 13	$ 42	$ 38
Interest cost		35	41	109	123
Expected return on plan assets		(62)	(62)	(185)	(184)
Amortization of: [Abstract]
Prior service cost		3	2	7	6
Actuarial loss		23	15	67	42
Net Periodic Defined Benefit Costs (Credits) Prior To Settlements		13	9	40	25
Settlements		13	0	13	1
Net periodic defined benefit costs (credits)		26	9	53	26
Pension Plan [Member] | U.K.
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		22	17	66	51
Interest cost		36	45	107	140
Expected return on plan assets		(155)	(144)	(464)	(442)
Amortization of: [Abstract]
Prior service cost		1	1	1	1
Actuarial loss		52	22	158	69
Net Periodic Defined Benefit Costs (Credits) Prior To Settlements		(44)	(59)	(132)	(181)
Settlements		0	0	0	0
Net periodic defined benefit costs (credits)		(44)	(59)	(132)	(181)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		2	2	5	4
Interest cost		4	5	14	16
Expected return on plan assets		(5)	(5)	(16)	(14)
Amortization of: [Abstract]
Prior service cost		0	0	1	0
Actuarial loss		0	1	0	1
Net periodic defined benefit costs (credits)		1	3	4	7
LKE [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Payment for Pension Benefits				22
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	3	9	8
LG And E And KU Energy LLC [Member]
Net Periodic Defined Benefit Costs Allocated to Subsidiary by Sponsor (Numeric) [Abstract]
Payment for Pension Benefits				22
LG And E And KU Energy LLC [Member] | Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		6	5	18	16
Interest cost		14	16	43	49
Expected return on plan assets		(25)	(25)	(75)	(76)
Amortization of: [Abstract]
Prior service cost		2	2	6	6
Actuarial loss		11	7	30	17
Net Periodic Defined Benefit Costs (Credits) Prior To Settlements		8	5	22	12
Settlements		13	0	13	0
Net periodic defined benefit costs (credits)		21	5	$ 35	$ 12
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		3	2	$ 9	$ 3
LG And E And KU Energy LLC [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost		1	1	3	3
Interest cost		2	2	6	6
Expected return on plan assets		(2)	(2)	(7)	(6)
Amortization of: [Abstract]
Prior service cost		1	0	1	1
Actuarial loss		(1)	0	(1)	(1)
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		9	1	14	3
Louisville Gas And Electric Co [Member] | Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost			0		1
Interest cost			2		8
Expected return on plan assets			(5)		(16)
Amortization of: [Abstract]
Prior service cost			1		4
Actuarial loss			4		7
Net periodic defined benefit costs (credits)			2		4
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		$ 4	$ 0	$ 5	$ 0