XML 144 R112.htm IDEA: XBRL DOCUMENT v3.20.4
FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($)
$ in Millions
1 Months Ended 10 Months Ended 12 Months Ended
Sep. 30, 2019
Sep. 30, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]          
Payment for settlement of interest rate swap accounted for as a cash flow hedge $ 69.8   $ 0.0 $ 69.8 $ 0.0
Notional amount 500.0 $ 500.0      
Other comprehensive loss   69.8 0.0 64.4 5.4
Interest expense     (383.9) (374.0) (279.6)
Income tax benefit     (102.2) (97.0) $ (59.0)
Accumulated other comprehensive loss over the next twelve months     5.4    
Senior Notes Due 2029 Evergy | Senior Notes          
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]          
Debt issued $ 800.0 $ 800.0      
Interest rate 2.90% 2.90%      
Debt instrument, term   10 years      
Reclassification out of Accumulated Other Comprehensive Income | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest          
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]          
Interest expense     7.0 2.0  
Income tax benefit     $ (4.0) $ (0.5)