v3.25.4
Equity (Narrative) (Details) - USD ($)
 1 Months Ended 3 Months Ended 12 Months Ended
Oct. 31, 2025
Oct. 28, 2025
Jun. 12, 2025
Mar. 03, 2025
Feb. 27, 2025
Oct. 31, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Mar. 15, 2024
Feb. 01, 2024
Dec. 01, 2023
Jun. 17, 2023
Jun. 15, 2023
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Common Stock Aggregate Sale Price $ 1,500,000,000         $ 1,500,000,000   $ 600,300,000   $ 600,300,000     $ 900,000,000.0      
Forward Contract Indexed to Issuer's Equity, Shares                   21,143,900            
Derivative, Forward Price $ 41.73   $ 39.71 $ 41 $ 40.10 $ 41.84                    
Preferred Stock, Liquidation Preference Per Share                               $ 1,000
Preferred Stock, Par or Stated Value Per Share               $ 0.01   $ 0.01       $ 0.01    
Shares Issued, Price Per Share $ 41.84         $ 41.84                    
Equity Units purchase contracts                 0 0 29,800,000          
Common Stock, Shares, Issued                           33,898,837    
ATM Program Equity Remaining Available for Issuance                 $ 1,350,000,000              
Preferred Stock Redemption Premium                   $ 14,000,000 $ 9,800,000          
Equity Units [Line Items]                                
Business Combination, Price of Acquisition, Expected   $ 35,200,000                            
Customer revenues             $ 6,522,800,000   6,522,800,000 5,282,900,000 5,347,800,000          
Direct Sale Agreement $ 1,195,029         $ 1,195,029                    
Forward February 27                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Derivative, Forward Price             $ 40.02                  
Series A Preferred Stock                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Preferred Stock, Liquidation Preference, Value             $ 400,000,000 $ 400,000,000 $ 400,000,000 400,000,000 400,000,000          
Preferred Stock, Redemption Amount                               $ 400,000,000
Preferred Stock, Shares Outstanding                               400,000
Preferred Stock, Dividends Per Share, Declared               $ 28.25                
Series B Preferred Stock                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Preferred Stock, Liquidation Preference Per Share             $ 25,000   $ 25,000              
Preferred Stock, Liquidation Preference, Value             $ 500,000,000 $ 500,000,000 $ 500,000,000 $ 500,000,000 $ 500,000,000          
Preferred Stock, Dividends Per Share, Declared                 $ 406.25 $ 1,625            
Series B-1 Preferred Stock                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Preferred Stock, Shares Issued               20,000   20,000   20,000        
Preferred Stock, Par or Stated Value Per Share                       $ 0.01        
Preferred Stock, Redemption Amount                       $ 500,000,000        
Series C Preferred Stock                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Preferred Stock, Liquidation Preference, Value             $ 863,000,000   $ 863,000,000              
Preferred Stock, Shares Outstanding                           862,500    
Forward February 27                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Common Stock Aggregate Sale Price         $ 80,000,000                      
Forward Contract Indexed to Issuer's Equity, Shares         2,000,000                      
Direct Sale Agreement 10.31.2025                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Common Stock Aggregate Sale Price $ 49,600,000         $ 49,600,000                    
NIPSCO Holdings II                                
Forward Contract Indexed to Issuer's Equity [Line Items]                                
Subsidiary, Ownership Percentage, Parent   19.90%                         19.90%  
Equity Units [Line Items]                                
Subsidiary, Ownership Percentage, Parent   19.90%                         19.90%