v3.26.1
FAIR VALUE MEASUREMENTS - Long-Term Debt (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Book Value | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-Term Debt $ 13,811.0 $ 13,406.2
Fair Value | Fair Value, Measurements, Recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt 13,140.7 13,018.9
Evergy Kansas Central | Book Value | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-Term Debt 5,234.8 5,233.1
Evergy Kansas Central | Fair Value | Fair Value, Measurements, Recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt 4,781.8 4,812.1
Evergy Metro | Book Value | Fair Value, Measurements, Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-Term Debt 3,272.0 3,271.4
Evergy Metro | Fair Value | Fair Value, Measurements, Recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt 3,080.6 3,122.7
Long-Term debt fair value adjustment    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt gross $ 73.5 $ 76.1