XML 108 R61.htm IDEA: XBRL DOCUMENT v3.21.1
Commitments and Contingencies - Legal Matters and Regulatory Issues (Details)
$ in Millions
1 Months Ended
Jun. 30, 2017
mi
Jul. 31, 2014
claim
Dec. 31, 2013
resident
Mar. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Jun. 01, 2015
Claim By Former Affiliate [Abstract]            
Percent of ownership of Talen Energy by Riverstone           35.00%
PPL Electric [Member] | PPL Electric Additional Sites [Member]            
Claim By Former Affiliate [Abstract]            
Accrual for Environmental Loss Contingencies | $       $ 10 $ 10  
LGE [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of residents that filed class action suit | resident     6      
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim   1        
LGE [Member] | Minimum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 1          
LGE [Member] | Maximum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 3          
PPL Electric Utilities Corp [Member] | PPL Electric Additional Sites [Member]            
Claim By Former Affiliate [Abstract]            
Accrual for Environmental Loss Contingencies | $       $ 10 $ 10  
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 | resident     6      
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim   1        
LG And E And KU Energy LLC [Member] | LGE [Member] | Minimum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 1          
LG And E And KU Energy LLC [Member] | LGE [Member] | Maximum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 3          
Louisville Gas And Electric Co [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of residents that filed class action suit | resident     6      
Number of remaining unresolved Clean Air Act violation claims after July 2014 court ruling | claim   1        
Louisville Gas And Electric Co [Member] | Minimum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 1          
Louisville Gas And Electric Co [Member] | Maximum [Member]            
Legal Matters - Cane Run Environmental Claims (Numeric) [Abstract]            
Number of miles within plant that would include a class of residents 3