Commitments and Contingencies - Legal Matters and Regulatory Issues (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) Integer claim resident coal-fired_unit mi
LGE [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit | resident	6
Number of miles within plant that would include a class of residents | mi	4
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim	1
Generating units retired at the Cane Run plant | coal-fired_unit	1
Additional generating units retired at the Cane Run plant | coal-fired_unit	2
Legal Matters - Mill Creek Environmental Claims (Numeric) [Abstract]
Amount agreed to fund in environmental enhancement projects | $	$ 1
LG And E And KU Energy LLC [Member] | LGE [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit	6
Number of miles within plant that would include a class of residents | mi	4
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling	1
Generating units retired at the Cane Run plant	1
Additional generating units retired at the Cane Run plant	2
Legal Matters - Mill Creek Environmental Claims (Numeric) [Abstract]
Amount agreed to fund in environmental enhancement projects | $	$ 1
Louisville Gas And Electric Co [Member]
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]
Number of residents that filed class action suit	6
Number of miles within plant that would include a class of residents | mi	4
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling	1
Generating units retired at the Cane Run plant	1
Additional generating units retired at the Cane Run plant	2
Legal Matters - Mill Creek Environmental Claims (Numeric) [Abstract]
Amount agreed to fund in environmental enhancement projects | $	$ 1