Regulatory Matters (Details) - Kansas City Power and Light Company [Member] - USD ($) $ in Millions	1 Months Ended
	May 31, 2017	Apr. 30, 2017	Nov. 30, 2016	Jul. 31, 2016
Missouri Public Service Commission [Member]
Regulatory Proceedings [Line Items]
Annual revenue increase, requested, portion related to rebasing fuel and purchased power expense				$ 27.2
Annual revenue increase, requested, not including rebasing fuel and purchased power expense				$ 62.9
Return on equity, requested (in hundredths)				9.90%
Rate-making equity ratio, requested (in hundredths)				49.88%
Annual revenue increase (decrease), approved	$ 32.5
Return on equity, approved (in hundredths)	9.50%
Ratemaking equity ratio, approved (in hundredths)	49.20%
Kansas Corporation Commission [Member]
Regulatory Proceedings [Line Items]
Annual revenue decrease, requested			$ 2.8
Public Utilities, KCPL and Commission Staff Recommended Rate Decrease, Amount		$ 3.6