v3.26.1
PENSION PLANS AND POST-RETIREMENT BENEFITS PENSION PLANS AND POST-RETIREMENT BENEFITS - Schedule of Components of Net Periodic Benefit Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax [Abstract]        
Total recognized in OCI or regulatory asset/liability $ (1.8) $ (1.3) $ (3.2) $ (2.7)
Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 10.3 11.3 20.6 22.6
Defined Benefit Plan, Interest Cost 24.1 23.6 48.3 47.1
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (22.6) (22.0) (45.2) (44.0)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) 0.5 0.4 1.0 0.9
Defined Benefit Plan, Amortization of Gain (Loss) (3.3) (4.6) (6.6) (9.2)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations 9.0 8.7 18.1 17.4
Defined Benefit Plan Regulatory Adjustment Net 4.8 4.1 8.7 7.3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total 13.8 12.8 26.8 24.7
Post-Retirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 0.4 0.3 0.8 0.7
Defined Benefit Plan, Interest Cost 2.0 2.5 4.1 5.0
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (2.1) (2.7) (4.2) (5.4)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) 0.1 0.1 0.1 0.2
Defined Benefit Plan, Amortization of Gain (Loss) (0.5) (1.0) (1.0) (2.0)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations (0.1) (0.8) (0.2) (1.5)
Defined Benefit Plan Regulatory Adjustment Net (0.5) (0.2) (1.0) (0.4)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total (0.6) (1.0) (1.2) (1.9)
Evergy Kansas Central | Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 4.2 4.7 8.3 9.3
Defined Benefit Plan, Interest Cost 12.0 11.9 24.1 23.8
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (11.1) (10.8) (22.2) (21.5)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) 0.5 0.5 1.0 1.0
Defined Benefit Plan, Amortization of Gain (Loss) 0.3 (0.1) 0.6 (0.2)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations 5.9 6.2 11.8 12.4
Defined Benefit Plan Regulatory Adjustment Net (1.7) (1.8) (3.9) (4.5)
Defined Benefit Plans Intercompany Allocations Net (0.3) (0.9) (0.6) (1.5)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total 3.9 3.5 7.3 6.4
Evergy Kansas Central | Post-Retirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 0.2 0.3 0.4 0.5
Defined Benefit Plan, Interest Cost 0.9 1.3 2.0 2.6
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (1.0) (1.4) (2.1) (2.8)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) 0.1 0.0 0.2 0.1
Defined Benefit Plan, Amortization of Gain (Loss) (0.3) (0.5) (0.6) (1.0)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations (0.1) (0.3) (0.1) (0.6)
Defined Benefit Plan Regulatory Adjustment Net (0.2) 0.0 (0.4) 0.0
Defined Benefit Plans Intercompany Allocations Net 0.0 0.0 (0.1) 0.0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total (0.3) (0.3) (0.6) (0.6)
Evergy Metro        
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax [Abstract]        
Total recognized in OCI or regulatory asset/liability 0.1 0.1 0.2 0.2
Evergy Metro | Pension Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 6.1 6.6 12.3 13.3
Defined Benefit Plan, Interest Cost 11.8 11.4 23.7 22.8
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (11.5) (11.2) (23.0) (22.5)
Defined Benefit Plan, Amortization of Gain (Loss) (3.3) (4.3) (6.8) (8.6)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations 3.1 2.5 6.2 5.0
Defined Benefit Plan Regulatory Adjustment Net 6.3 5.7 12.3 11.5
Defined Benefit Plans Intercompany Allocations Net (0.7) 0.2 (1.2) 0.3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total 8.7 8.4 17.3 16.8
Evergy Metro | Post-Retirement Benefits        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 0.2 0.2 0.4 0.3
Defined Benefit Plan, Interest Cost 1.1 1.3 2.2 2.5
Defined Benefit Plan, Expected Return (Loss) on Plan Assets (1.1) (1.4) (2.3) (2.7)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) (0.1) (0.1) (0.2) (0.2)
Defined Benefit Plan, Amortization of Gain (Loss) (0.2) (0.6) (0.4) (1.0)
Net Period Benefit Costs Before Regulatory Adjustment And Intercompany Allocations (0.1) (0.6) (0.3) (1.1)
Defined Benefit Plan Regulatory Adjustment Net (0.2) (0.2) (0.5) (0.3)
Defined Benefit Plans Intercompany Allocations Net 0.1 0.3 0.3 0.4
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Total $ (0.2) $ (0.5) $ (0.5) $ (1.0)