Accumulated Other Comprehensive Income (Loss) - After-tax Changes by Component (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (4,602)	$ (3,996)	$ (4,358)	$ (3,964)
Amounts arising during the period	575	(274)	258	(346)
Reclassifications from AOCI	100	(2)	173	38
Net OCI during the period	675	(276)	431	(308)
Balance at end of period	(3,927)	(4,272)	(3,927)	(4,272)
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(1,777)	(1,616)	(1,425)	(1,533)
Amounts arising during the period	643	(285)	291	(368)
Reclassifications from AOCI	0	0	0	0
Net OCI during the period	643	(285)	291	(368)
Balance at end of period	(1,134)	(1,901)	(1,134)	(1,901)
Unrealized gains (losses) on qualifying derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	8	6	(5)	(7)
Amounts arising during the period	(52)	16	(16)	32
Reclassifications from AOCI	48	(22)	25	(25)
Net OCI during the period	(4)	(6)	9	7
Balance at end of period	4	0	4	0
Defined benefit plans Prior service costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(16)	(18)	(18)	(19)
Amounts arising during the period	0	0	0	0
Reclassifications from AOCI	0	0	2	1
Net OCI during the period	0	0	2	1
Balance at end of period	(16)	(18)	(16)	(18)
Defined benefit plans Actuarial gain (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(2,817)	(2,368)	(2,910)	(2,405)
Amounts arising during the period	(16)	(5)	(17)	(10)
Reclassifications from AOCI	52	20	146	62
Net OCI during the period	36	15	129	52
Balance at end of period	(2,781)	(2,353)	(2,781)	(2,353)
LG And E And KU Energy LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(91)	(91)	(93)	(89)
Amounts arising during the period	(8)	0	(9)	(2)
Reclassifications from AOCI	5	0	8	0
Net OCI during the period	(3)	0	(1)	(2)
Balance at end of period	(94)	(91)	(94)	(91)
LG And E And KU Energy LLC [Member] | Defined benefit plans Prior service costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(8)	(8)	(9)	(9)
Amounts arising during the period	0	0	0	0
Reclassifications from AOCI	0	0	1	1
Net OCI during the period	0	0	1	1
Balance at end of period	(8)	(8)	(8)	(8)
LG And E And KU Energy LLC [Member] | Defined benefit plans Actuarial gain (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(83)	(83)	(84)	(80)
Amounts arising during the period	(8)	0	(9)	(2)
Reclassifications from AOCI	5	0	7	(1)
Net OCI during the period	(3)	0	(2)	(3)
Balance at end of period	$ (86)	$ (83)	$ (86)	$ (83)