Derivative Instruments Offsetting Assets (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
FIN 39 Derivative asset netting
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Derivative Asset, Current	$ 50.2	$ 17.3
Derivative Asset, Noncurrent	$ 27.0	$ 27.1
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 143.5	$ 82.3
Commodity contract current
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	98.7	47.2
FIN 39 Derivative asset netting
Gross amounts offset	(48.5)	(29.9)
Commodity contract noncurrent
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	44.8	35.1
FIN 39 Derivative asset netting
Gross amounts offset	(17.8)	(8.0)
Power commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	92.0	40.8
Power commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	44.8	35.1
Natural gas commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	6.7	6.4
Interest Rate Swap [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	1.2	0.6
InterestRateSwapNoncurrent [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	1.2	0.6
Evergy Kansas Central
FIN 39 Derivative asset netting
Derivative Asset, Current	19.9	12.8
Derivative Asset, Noncurrent	27.0	27.1
Evergy Kansas Central \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	111.9	74.9
Evergy Kansas Central \| Commodity contract current
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	67.1	39.8
FIN 39 Derivative asset netting
Gross amounts offset	(47.2)	(27.0)
Evergy Kansas Central \| Commodity contract noncurrent
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	44.8	35.1
FIN 39 Derivative asset netting
Gross amounts offset	(17.8)	(8.0)
Evergy Kansas Central \| Power commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	60.4	33.4
Evergy Kansas Central \| Power commodity contract noncurrent \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	44.8	35.1
Evergy Kansas Central \| Natural gas commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	6.7	6.4
Evergy Metro
FIN 39 Derivative asset netting
Derivative Asset, Current	28.2	4.3
Derivative Asset, Noncurrent	0.0	0.0
Evergy Metro \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	29.2	6.6
Evergy Metro \| Commodity contract current
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	29.2	6.6
FIN 39 Derivative asset netting
Gross amounts offset	(1.0)	(2.3)
Evergy Metro \| Commodity contract noncurrent
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	0.0	0.0
FIN 39 Derivative asset netting
Gross amounts offset	0.0	0.0
Evergy Metro \| Power commodity contract current \| Not Designated as Hedging Instrument [Member]
Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 29.2	$ 6.6

Indicates line item in statement of financial position that includes derivative asset classified as current.

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Fair value of liability associated with financial asset or other 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 obligation to return cash collateral under master netting arrangements.

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

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Fair value, before effects of master netting arrangements, of a financial asset or other 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 assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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