v3.24.2
INVESTMENT IN TRANSMISSION AFFILIATES - SUMMARIZED FINANCIAL DATA (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Dec. 31, 2023
Summarized financial data          
Operating revenues $ 1,772.0 $ 1,830.0 $ 4,452.2 $ 4,718.1  
Operating expenses 1,407.2 1,404.7 3,274.0 3,623.5  
Other expense, net 113.2 86.8 216.3 174.4  
Current assets 2,584.1   2,584.1   $ 2,795.7
Noncurrent assets 41,998.1   41,998.1   41,144.0
Total assets 44,582.2   44,582.2   43,939.7
Current liabilities 3,491.6   3,491.6   5,114.8
Other noncurrent liabilities 794.2   794.2   835.3
Total liabilities and members' equity 44,582.2   44,582.2   43,939.7
ATC          
Summarized financial data          
Operating revenues 218.3 203.8 430.2 404.2  
Operating expenses 109.2 101.5 214.0 200.6  
Other expense, net 35.8 32.9 71.0 65.4  
Net income 73.3 $ 69.4 145.2 $ 138.2  
Current assets 146.5   146.5   115.2
Noncurrent assets 6,539.3   6,539.3   6,337.0
Total assets 6,685.8   6,685.8   6,452.2
Current liabilities 586.0   586.0   495.9
Long-term debt 2,810.5   2,810.5   2,736.0
Other noncurrent liabilities 573.3   573.3   585.2
Members' equity 2,716.0   2,716.0   2,635.1
Total liabilities and members' equity $ 6,685.8   $ 6,685.8   $ 6,452.2