CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax effect of foreign currency translation adjustments arising during the period	$ (1)	$ (4)	$ 1
Tax effect of available-for-sale securities arising during the period	0	0	(9)
Tax effect of qualifying derivatives arising during the period	19	(18)	0
Tax effect of defined benefit plans - prior service costs arising during period	0	2	6
Tax effect of defined benefit plans - net actuarial gain (loss) arising during period	72	40	67
Tax effect of available-for-sale securities reclassified to net income	0	0	2
Tax effect of qualifying derivatives reclassified to net income	(18)	21	(15)
Tax effect of equity investees' other comprehensive (income) loss reclassified to net income	0	0	0
Tax effect of defined benefit plans - prior service costs reclassified to net income	(1)	(1)	0
Tax effect of defined benefit plans - net actuarial (gain) loss reclassified to net income	(37)	(35)	(46)
LG And E And KU Energy LLC [Member]
Tax effect of defined benefit plans - prior service costs arising during period	(1)	0	(2)
Tax effect of defined benefit plans - net actuarial gain (loss) arising during period	13	18	2
Tax effect of equity investees' other comprehensive (income) loss reclassified to net income	0	0	0
Tax effect of defined benefit plans - prior service costs reclassified to net income	1	1	1
Tax effect of defined benefit plans - net actuarial (gain) loss reclassified to net income	$ 2	$ 1	$ 3