XML 107 R95.htm IDEA: XBRL DOCUMENT v3.20.2
INVESTMENT IN TRANSMISSION AFFILIATES - RELATED PARTY TRANSACTIONS (Details) - ATC - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Investment in transmission affiliates        
Charges to ATC for services and construction $ 5.7 $ 9.2 $ 18.7 $ 16.5
Charges from ATC for network transmission services $ 85.5 $ 86.9 $ 252.0 $ 261.0