v3.25.4
Risk Management Activities (Narrative) (Details)
mMDth in Millions, $ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
mMDth
Aug. 15, 2025
Jun. 27, 2025
USD ($)
Mar. 27, 2025
USD ($)
Dec. 31, 2024
USD ($)
mMDth
Derivative [Line Items]          
Limit of GCA Volumes 20.00%        
Derivative Asset $ 18.8        
Senior Notes 13,253.0       $ 12,103.0
Derivative Asset, Subject to Master Netting Arrangement, after Offset $ 12.9       23.5
Customer annual demand 20.00%        
Other Current Assets          
Derivative [Line Items]          
Derivative Asset $ 9.7       $ 9.1
NiSource          
Derivative [Line Items]          
Senior Notes     $ 900.0    
Senior Notes | NiSource          
Derivative [Line Items]          
Senior Notes $ 1,500.0   $ 750.0 $ 750.0  
Debt, Weighted Average Interest Rate   0.95% 5.85% 5.85%  
Minimum          
Derivative [Line Items]          
Commodity Contract Length 1 year        
Maximum          
Derivative [Line Items]          
Commodity Contract Length 3 years        
Natural Gas          
Derivative [Line Items]          
Derivative, Nonmonetary Notional Amount | mMDth 83.7       77.8