Goodwill and Other Intangible Assets (Goodwill) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period		$ 3,667	$ 3,805	[1]
Effect of foreign currency exchange rates		(117)	(138)
Balance at end of period		3,550	3,667
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
United Kingdom Regulated [Member]
Changes in the Carrying Amount of Goodwill by Segment [Roll Forward]
Balance at beginning of period	[1]	3,005	3,143
Effect of foreign currency exchange rates		(117)	(138)
Balance at end of period	[1]	2,888	3,005
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.