Derivative Instruments Offsetting Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
Derivative Liability, Current	$ 19.9	$ 8.2
Derivative Liability, Noncurrent	$ 30.2	$ 29.6
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	$ 116.0	$ 74.6
Power commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	47.8	37.0
Commodity contract current
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	68.2	37.5
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	(48.3)	(29.3)
Commodity contract noncurrent
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	47.8	37.1
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	(17.6)	(7.5)
Power commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	60.7	30.8
Natural gas commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	7.5	6.7
Natural gas commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.0	0.1
Evergy Kansas Central
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
Derivative Liability, Current	19.9	8.2
Derivative Liability, Noncurrent	30.2	29.6
Evergy Kansas Central \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	114.6	71.7
Evergy Kansas Central \| Power commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	47.8	37.0
Evergy Kansas Central \| Commodity contract current
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	66.8	34.6
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	(46.9)	(26.4)
Evergy Kansas Central \| Commodity contract noncurrent
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	47.8	37.1
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	(17.6)	(7.5)
Evergy Kansas Central \| Power commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	59.3	27.9
Evergy Kansas Central \| Natural gas commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	7.5	6.7
Evergy Kansas Central \| Natural gas commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.0	0.1
Evergy Metro
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
Derivative Liability, Current	0.0	0.0
Derivative Liability, Noncurrent	0.0	0.0
Evergy Metro \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	1.0	2.3
Evergy Metro \| Commodity contract current
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	1.0	2.3
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	(1.0)	(2.3)
Evergy Metro \| Commodity contract noncurrent
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.0	0.0
Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset [Abstract]
FIN 39 Derivative liability netting	0.0	0.0
Evergy Metro \| Natural gas commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Gross Liability	$ 1.0	$ 2.3

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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- Definition

Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and right to receive cash collateral under master netting arrangements.

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Indicates line item in statement of financial position that includes derivative liability classified as noncurrent.

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