XML 141 R109.htm IDEA: XBRL DOCUMENT v3.20.4
LONG-TERM DEBT (Details) - USD ($)
$ in Millions
Dec. 31, 2020
May 31, 2020
Apr. 30, 2020
Dec. 31, 2019
Debt Instrument [Line Items]        
Long-term Debt, Current Maturities $ (436.4)     $ (251.1)
Unamortized debt discount and debt issuance costs (84.9)     (80.7)
Total excluding current maturities 9,190.9     8,746.7
Fair Value adjustment        
Debt Instrument [Line Items]        
Long-term debt gross 110.4     125.5
Long-term Debt, Current Maturities $ (4.4)     $ (4.3)
Mortgage Bonds | Mortgage Bonds Due 2020 EKC        
Debt Instrument [Line Items]        
Interest rate       5.10%
Long-term debt gross       $ 250.0
Mortgage Bonds | Mortgage Bonds Due 2025 EKC        
Debt Instrument [Line Items]        
Interest rate 3.25%     3.25%
Long-term debt gross $ 250.0     $ 250.0
Mortgage Bonds | Mortgage Bonds Due 2026 EKC        
Debt Instrument [Line Items]        
Interest rate 2.55%     2.55%
Long-term debt gross $ 350.0     $ 350.0
Mortgage Bonds | Mortgage Bonds Due 2027 EKC        
Debt Instrument [Line Items]        
Interest rate 3.10%     3.10%
Long-term debt gross $ 300.0     $ 300.0
Mortgage Bonds | Mortgage Bonds Due 2042 EKC        
Debt Instrument [Line Items]        
Interest rate 4.125%     4.125%
Long-term debt gross $ 550.0     $ 550.0
Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Interest rate 4.10%     4.10%
Long-term debt gross $ 430.0     $ 430.0
Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Interest rate 4.625%     4.625%
Long-term debt gross $ 250.0     $ 250.0
Mortgage Bonds | Mortgage Bonds Due 2045 EKC        
Debt Instrument [Line Items]        
Interest rate 4.25%     4.25%
Long-term debt gross $ 300.0     $ 300.0
Mortgage Bonds | Mortgage Bonds Due 2049 EKC        
Debt Instrument [Line Items]        
Interest rate 3.25%     3.25%
Long-term debt gross $ 300.0     $ 300.0
Mortgage Bonds | Mortgage Bonds Due 2050 EKC        
Debt Instrument [Line Items]        
Interest rate 3.45%      
Long-term debt gross $ 500.0      
Mortgage Bonds | Mortgage Bonds Due 2023 EKS        
Debt Instrument [Line Items]        
Interest rate 6.15%     6.15%
Long-term debt gross $ 50.0     $ 50.0
Mortgage Bonds | Mortgage Bonds Due 2037 EKS        
Debt Instrument [Line Items]        
Interest rate 6.53%     6.53%
Long-term debt gross $ 175.0     $ 175.0
Mortgage Bonds | Mortgage Bonds Due 2038 EKS        
Debt Instrument [Line Items]        
Interest rate 6.64%     6.64%
Long-term debt gross $ 100.0     $ 100.0
Mortgage Bonds | Mortgage Bonds Due 2044 EKS        
Debt Instrument [Line Items]        
Interest rate 4.30%     4.30%
Long-term debt gross $ 250.0     $ 250.0
Mortgage Bonds | Mortgage Bonds Due 2023 EM        
Debt Instrument [Line Items]        
Interest rate 2.95%     2.95%
Long-term debt gross $ 79.5     $ 79.5
Mortgage Bonds | Mortgage Bonds Due 2030 EM        
Debt Instrument [Line Items]        
Interest rate 2.25%      
Long-term debt gross $ 400.0      
Mortgage Bonds | Mortgage Bonds Due 2049 EM        
Debt Instrument [Line Items]        
Interest rate 4.125%     4.125%
Long-term debt gross $ 400.0     $ 400.0
Mortgage Bonds | Mortgage Bonds Due Through 2021-2021 EMW        
Debt Instrument [Line Items]        
Interest rate 9.44%     9.44%
Long-term debt gross $ 1.1     $ 2.3
Pollution Control Bonds | Pollution Control Bonds Due 2032A EKC        
Debt Instrument [Line Items]        
Interest rate 0.18%     1.39%
Long-term debt gross $ 45.0     $ 45.0
Pollution Control Bonds | Pollution Control Bonds Due 2032B EKC        
Debt Instrument [Line Items]        
Interest rate 0.18%     1.39%
Long-term debt gross $ 30.5     $ 30.5
Pollution Control Bonds | Pollution Control Bonds Due 2027 EKS        
Debt Instrument [Line Items]        
Interest rate 0.18%     1.39%
Long-term debt gross $ 21.9     $ 21.9
Pollution Control Bonds | Pollution Control Bonds Due 2031 EKS        
Debt Instrument [Line Items]        
Interest rate 2.50%     2.50%
Long-term debt gross $ 50.0     $ 50.0
Pollution Control Bonds | Pollution Control Bonds Due 2032A EKS        
Debt Instrument [Line Items]        
Interest rate 0.18%     1.39%
Long-term debt gross $ 14.5     $ 14.5
Pollution Control Bonds | Pollution Control Bonds Due 2032B EKS        
Debt Instrument [Line Items]        
Interest rate 1.39%     1.39%
Long-term debt gross $ 10.0     $ 10.0
Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2035 EM        
Debt Instrument [Line Items]        
Interest rate 1.432%     1.432%
Long-term debt gross $ 146.5     $ 146.5
Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2038 EM        
Debt Instrument [Line Items]        
Interest rate 2.75%     2.75%
Long-term debt gross $ 23.4     $ 23.4
Senior Notes | Series Notes Due 2023 EM        
Debt Instrument [Line Items]        
Interest rate 3.15%     3.15%
Long-term debt gross $ 300.0     $ 300.0
Senior Notes | Senior Notes Due 2025 EM        
Debt Instrument [Line Items]        
Interest rate 3.65%     3.65%
Long-term debt gross $ 350.0     $ 350.0
Senior Notes | Senior Notes Due 2035 EM        
Debt Instrument [Line Items]        
Interest rate 6.05%     6.05%
Long-term debt gross $ 250.0     $ 250.0
Senior Notes | Senior Notes Due 2035A EM        
Debt Instrument [Line Items]        
Interest rate 5.78%     5.78%
Senior Notes | Senior Notes Due 2041 EM        
Debt Instrument [Line Items]        
Interest rate 5.30%     5.30%
Long-term debt gross $ 400.0     $ 400.0
Senior Notes | Senior Notes Due 2047 EM        
Debt Instrument [Line Items]        
Interest rate 4.20%     4.20%
Long-term debt gross $ 300.0     $ 300.0
Senior Notes | Senior Notes Due 2048 EM        
Debt Instrument [Line Items]        
Interest rate 4.20%     4.20%
Long-term debt gross $ 300.0     $ 300.0
Senior Notes | Senior Notes Due 2021 EMW        
Debt Instrument [Line Items]        
Interest rate 8.27%     8.27%
Long-term debt gross $ 80.9     $ 80.9
Senior Notes | Senior Notes Due 2025 EMW        
Debt Instrument [Line Items]        
Interest rate 3.49%     3.49%
Long-term debt gross $ 36.0     $ 36.0
Senior Notes | Senior Notes Due 2033 EMW        
Debt Instrument [Line Items]        
Interest rate 4.06%     4.06%
Long-term debt gross $ 60.0     $ 60.0
Senior Notes | Senior Notes Due 2043 EMW        
Debt Instrument [Line Items]        
Interest rate 4.74%     4.74%
Long-term debt gross $ 150.0     $ 150.0
Senior Notes | Senior Notes Series Due 2022 EMW        
Debt Instrument [Line Items]        
Interest rate 3.74%     3.74%
Long-term debt gross $ 100.0     $ 100.0
Senior Notes | Senior Notes Due 2021        
Debt Instrument [Line Items]        
Interest rate 4.85%     4.85%
Long-term debt gross $ 350.0     $ 350.0
Senior Notes | Senior Notes Due 2022        
Debt Instrument [Line Items]        
Interest rate 5.292%     5.292%
Long-term debt gross $ 287.5     $ 287.5
Senior Notes | Senior Notes Due 2024        
Debt Instrument [Line Items]        
Interest rate 2.45%     2.45%
Long-term debt gross $ 800.0     $ 800.0
Senior Notes | Senior Notes Due 2029        
Debt Instrument [Line Items]        
Interest rate 2.90%     2.90%
Long-term debt gross $ 800.0     $ 800.0
Senior Notes | Senior Notes Due 2029A        
Debt Instrument [Line Items]        
Interest rate 3.77%     3.77%
Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Interest rate 7.33%     7.33%
Long-term debt gross $ 3.0     $ 3.0
Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Interest rate 7.17%     7.17%
Long-term debt gross $ 7.0     $ 7.0
Evergy Kansas Central        
Debt Instrument [Line Items]        
Long-term Debt, Current Maturities 0.0     (250.0)
Unamortized debt discount and debt issuance costs (45.4)     (40.8)
Total excluding current maturities 3,931.5     3,436.1
Evergy Kansas Central | Fair Value adjustment        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2020 EKC        
Debt Instrument [Line Items]        
Interest rate     5.10%  
Long-term debt gross     $ 250.0 250.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2025 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 250.0     250.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2026 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 350.0     350.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2027 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2042 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 550.0     550.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 430.0     430.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 250.0     250.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2045 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2049 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2050 EKC        
Debt Instrument [Line Items]        
Interest rate     3.45%  
Long-term debt gross 500.0   $ 500.0  
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2023 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 50.0     50.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2037 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 175.0     175.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2038 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 100.0     100.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2044 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 250.0     250.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2023 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2030 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0      
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due 2049 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Mortgage Bonds | Mortgage Bonds Due Through 2021-2021 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2032A EKC        
Debt Instrument [Line Items]        
Long-term debt gross 45.0     45.0
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2032B EKC        
Debt Instrument [Line Items]        
Long-term debt gross 30.5     30.5
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2027 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 21.9     21.9
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2031 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 50.0     50.0
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2032A EKS        
Debt Instrument [Line Items]        
Long-term debt gross 14.5     14.5
Evergy Kansas Central | Pollution Control Bonds | Pollution Control Bonds Due 2032B EKS        
Debt Instrument [Line Items]        
Long-term debt gross 10.0     10.0
Evergy Kansas Central | Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2035 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2038 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Series Notes Due 2023 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2025 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2035 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2041 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2047 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2048 EM        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2021 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2025 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2033 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2043 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Series Due 2022 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2021        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2022        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2024        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Senior Notes | Senior Notes Due 2029        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Kansas Central | Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro        
Debt Instrument [Line Items]        
Long-term Debt, Current Maturities 0.0     0.0
Unamortized debt discount and debt issuance costs (26.4)     (24.4)
Total excluding current maturities 2,923.0     2,525.0
Evergy Metro | Fair Value adjustment        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2020 EKC        
Debt Instrument [Line Items]        
Long-term debt gross       0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2025 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2026 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2027 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2042 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2043 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2045 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2049 EKC        
Debt Instrument [Line Items]        
Long-term debt gross    
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2050 EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0      
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2023 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2037 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2038 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2044 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2023 EM        
Debt Instrument [Line Items]        
Long-term debt gross 79.5     79.5
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2030 EM        
Debt Instrument [Line Items]        
Interest rate   2.25%    
Long-term debt gross 400.0 $ 400.0    
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due 2049 EM        
Debt Instrument [Line Items]        
Long-term debt gross 400.0     400.0
Evergy Metro | Mortgage Bonds | Mortgage Bonds Due Through 2021-2021 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Mortgage Bonds | General Mortgage Bonds EIRR Series 2005        
Debt Instrument [Line Items]        
Long-term debt gross 50.0     21.9
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2032A EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2032B EKC        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2027 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2031 EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2032A EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | Pollution Control Bonds Due 2032B EKS        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2035 EM        
Debt Instrument [Line Items]        
Long-term debt gross 146.5     146.5
Evergy Metro | Pollution Control Bonds | EIRR Bonds Series 2007A and 2007B due 2038 EM        
Debt Instrument [Line Items]        
Long-term debt gross 23.4     23.4
Evergy Metro | Senior Notes | Series Notes Due 2023 EM        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Metro | Senior Notes | Senior Notes Due 2025 EM        
Debt Instrument [Line Items]        
Long-term debt gross 350.0     350.0
Evergy Metro | Senior Notes | Senior Notes Due 2035 EM        
Debt Instrument [Line Items]        
Long-term debt gross 250.0     250.0
Evergy Metro | Senior Notes | Senior Notes Due 2041 EM        
Debt Instrument [Line Items]        
Long-term debt gross 400.0     400.0
Evergy Metro | Senior Notes | Senior Notes Due 2047 EM        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Metro | Senior Notes | Senior Notes Due 2048 EM        
Debt Instrument [Line Items]        
Long-term debt gross 300.0     300.0
Evergy Metro | Senior Notes | Senior Notes Due 2021 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2025 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2033 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2043 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Series Due 2022 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2021        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2022        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2024        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Senior Notes | Senior Notes Due 2029        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Evergy Metro | Medium Term Notes | Medium Term Notes Due 2023 EMW        
Debt Instrument [Line Items]        
Long-term debt gross 0.0     0.0
Variable Interest Entities        
Debt Instrument [Line Items]        
Long-term Debt, Current Maturities (18.8)     (32.3)
Total excluding current maturities 0.0     18.8
Variable Interest Entities | Unsecured Debt | Unsecured Debt Due 2021 VIEs        
Debt Instrument [Line Items]        
Long-term debt gross 18.8     51.1
Long-term Debt, Current Maturities (18.8)     (32.3)
Total excluding current maturities 0.0     18.8
Variable Interest Entities | Evergy Kansas Central        
Debt Instrument [Line Items]        
Long-term Debt, Current Maturities (18.8)     (32.3)
Total excluding current maturities $ 0.0     $ 18.8