Accumulated Other Comprehensive Income (Loss) (After-tax Changes by Component) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	$ (3,422)	$ (3,778)	$ (2,728)
Amounts arising during the year	(606)	151	(1,080)
Reclassifications from AOCI	115	205	30
Net OCI during the year	(491)	356	(1,050)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(51)
Balance at end of year	(3,964)	(3,422)	(3,778)
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(1,089)	(1,627)	(520)
Amounts arising during the year	(444)	538	(1,107)
Reclassifications from AOCI	0	0	0
Net OCI during the year	(444)	538	(1,107)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	0
Balance at end of year	(1,533)	(1,089)	(1,627)
Qualifying Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(13)	(7)	(7)
Amounts arising during the year	36	(79)	91
Reclassifications from AOCI	(29)	73	(91)
Net OCI during the year	7	(6)	0
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(1)
Balance at end of year	(7)	(13)	(7)
Equity Investees AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	0	(1)	0
Amounts arising during the year	0	0	0
Reclassifications from AOCI	0	1	(1)
Net OCI during the year	0	1	(1)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	0
Balance at end of year	0	0	(1)
Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(7)	(8)	(6)
Amounts arising during the year	(11)	0	(3)
Reclassifications from AOCI	2	1	1
Net OCI during the year	(9)	1	(2)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(3)
Balance at end of year	(19)	(7)	(8)
Defined Benefit Plans Actuarial Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(2,313)	(2,135)	(2,195)
Amounts arising during the year	(187)	(308)	(61)
Reclassifications from AOCI	142	130	121
Net OCI during the year	(45)	(178)	60
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(47)
Balance at end of year	(2,405)	(2,313)	(2,135)
LG And E And KU Energy LLC [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(88)	(70)	(46)
Amounts arising during the year	7	(25)	(27)
Reclassifications from AOCI	10	7	3
Net OCI during the year	17	(18)	(24)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(18)
Balance at end of year	(89)	(88)	(70)
LG And E And KU Energy LLC [Member] | Equity Investees AOCI [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	0	(1)	0
Amounts arising during the year	0	0	0
Reclassifications from AOCI	0	1	(1)
Net OCI during the year	0	1	(1)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	0
Balance at end of year	0	0	(1)
LG And E And KU Energy LLC [Member] | Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of year	(9)	(8)	(10)
Amounts arising during the year	0	(2)	0
Reclassifications from AOCI	2	1	2
Net OCI during the year	2	(1)	2
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(2)
Balance at end of year	(9)	(9)	(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 year	(79)	(61)	(36)
Amounts arising during the year	7	(23)	(27)
Reclassifications from AOCI	8	5	2
Net OCI during the year	15	(18)	(25)
Adoption of reclassification of certain tax effects from AOCI guidance cumulative effect adjustment	(16)
Balance at end of year	$ (80)	$ (79)	$ (61)