Goodwill and Other Intangible Assets (Goodwill) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period	[1]	$ 3,550	$ 3,667
Effect of foreign currency exchange rates		(490)	(117)
Balance at end of period	[1]	3,060	3,550
U.K. Regulated [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period	[1]	2,888	3,005
Effect of foreign currency exchange rates		(490)	(117)
Balance at end of period	[1]	2,398	2,888
Kentucky Regulated [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period	[1]	662	662
Balance at end of period	[1]	662	662
LG And E And KU Energy LLC [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period		996
Balance at end of period		996	996
Louisville Gas And Electric Co [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period		389
Balance at end of period		389	389
Kentucky Utilities Co [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period		607
Balance at end of period		$ 607	$ 607

[1] There were no accumulated impairment losses related to goodwill.