v3.25.2
LONG-TERM DEBT (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Debt Instrument [Line Items]    
Long-Term Debt $ 2,400,627 $ 2,414,256
Debt Instrument, Unamortized Discount (3,725) (3,624)
Debt Issuance Costs, Net (19,664) (20,691)
Long-term debt, current maturities 14 14
Long-term Debt, excluding current maturities 2,370,863 2,385,286
Debt Instrument, Covenant Compliance, Default Provision, Indebtnedness Threshold $ 100,000  
Debt Instrument, Covenant Compliance, Default Provision, Debt Holders 25.00%  
Debt Instrument, Redemption Price, Percentage 100.00%  
Kansas Gas Service Securitization I LLC    
Debt Instrument [Line Items]    
Debt Issuance Costs, Net $ (4,500) (4,800)
5.10% Senior Unsecured Notes Due 2029 [Member]    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.10%  
Long-term Debt, Gross $ 550,000 550,000
2.00% Senior Unsecured Notes Due 2030    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.00%  
Long-term Debt, Gross $ 300,000 300,000
4.25% Senior Unsecured Notes Due 2032    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.25%  
Long-term Debt, Gross $ 300,000 300,000
4.658% Senior Unsecured Notes Due 2044    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.658%  
Long-term Debt, Gross $ 600,000 600,000
4.50% Senior Unsecured Notes Due 2048    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.50%  
Long-term Debt, Gross $ 400,000 400,000
Total Senior Unsecured Notes    
Debt Instrument [Line Items]    
Long-term Debt, Gross $ 2,150,000 2,150,000
5.486% KGSS-I Securitized Utility Tariff Bonds Due 2032    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.486%  
Long-term Debt, Gross $ 272,798 287,345
Long-term debt, current maturities $ 29,750 28,956
8.00% Other Long Term Debt    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 8.00%  
Long-term Debt, Gross $ 1,218 $ 1,226