XML 112 R94.htm IDEA: XBRL DOCUMENT v3.24.0.1
Income Taxes (Narrative) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2023
Dec. 31, 2023
Income Taxes [Line Items]          
Deferred Tax Assets, Operating Loss Carryforwards $ 422.9 $ 491.0      
Deferred Tax Assets, Valuation Allowance $ 6.4 $ 7.8      
Effective Income Tax Rate Reconciliation, Tax Accrual Adjustments, Percent 0.00% 0.00% 0.00%    
Book income before income taxes $ 813.9 $ 956.4 $ 706.6    
Tax expense (benefit) at statutory federal income tax rate, value $ 170.8 $ 200.8 $ 148.3    
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent 21.00% 21.00% 21.00%    
State income taxes, net of federal income tax benefit, value $ 13.7 $ 4.5 $ 14.1    
State income taxes, net of federal income tax benefit, rate 1.70% 0.50% 2.00%    
Amortization of regulatory liabilities, value $ (38.2) $ (38.5) $ (39.1)    
Amortization of regulatory liabilities, rate (4.70%) (4.00%) (5.50%)    
Fines and penalties, value $ 0.0 $ 0.3 $ 0.0    
Fines and penalties, rate 0.00% 0.00% 0.00%    
Effective Income Tax Rate Reconciliation, Deduction, Employee Stock Ownership Plan Dividend, Amount $ (1.3) $ (1.2) $ (1.2)    
Employee stock ownership plan dividends and other compensation, rate (0.20%) (0.10%) (0.20%)    
Effective Income Tax Rate Reconciliation Tax Accrual Adjustments $ 0.0 $ 0.2 $ (0.1)    
Effective Income Tax Rate Reconciliation, Tax Credit, Amount $ (4.9) $ (2.3) $ (2.1)    
Effective Income Tax Rate Reconciliation, Tax Credit, Percent (0.60%) (0.20%) (0.30%)    
Other adjustments, value $ (0.6) $ 0.8 $ (2.1)    
Other adjustments, rate (0.10%) 0.00% (0.30%)    
Income Taxes $ 139.5 $ 164.6 $ 117.8    
Effective Income Tax Rate Reconciliation, Percent 17.10% 17.20% 16.70%    
Deferred Federal Income Tax Expense (Benefit) $ (458.6)        
Increase (Decrease) in Tax Expense 25.1 $ 46.8      
Operating Loss Carryforwards 21.7 21.7 $ 21.7    
NiSource          
Income Taxes [Line Items]          
Subsidiary, Ownership Percentage, Parent       80.10% 80.10%
Investment Tax Credit Carryforward          
Income Taxes [Line Items]          
Deferred Tax Assets, Valuation Allowance 0.0        
Deferred Federal Income Tax Expense (Benefit) (2.1) $ 0.0 $ 0.0    
Federal production tax credits          
Income Taxes [Line Items]          
Deferred Tax Assets, Valuation Allowance 0.0        
Deferred Federal Income Tax Expense (Benefit) (0.8)        
Federal other credit          
Income Taxes [Line Items]          
Deferred Tax Assets, Valuation Allowance 0.0        
Deferred Federal Income Tax Expense (Benefit) (15.7)        
State and Local Jurisdiction          
Income Taxes [Line Items]          
Deferred Federal, State and Local, Tax Expense (Benefit) 95.1        
Domestic Tax Authority          
Income Taxes [Line Items]          
Deferred Federal Income Tax Expense (Benefit) (344.9)        
State and Local Jurisdiction          
Income Taxes [Line Items]          
Deferred Tax Assets, Valuation Allowance 6.4        
Operating Loss Carryforwards 2,371.7        
Domestic Tax Authority          
Income Taxes [Line Items]          
Deferred Tax Assets, Valuation Allowance 0.0        
Operating Loss Carryforwards $ 1,642.4