Pension Plans and Other Employee Benefits (Tables)

3 Months Ended

Mar. 31, 2016

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs [Table Text Block]

The following table provides Great Plains Energy's components of net periodic benefit costs prior to the effects of capitalization and sharing with joint owners of power plants.

	Pension Benefits						Other Benefits
Three Months Ended March 31	2016			2015			2016			2015
Components of net periodic benefit costs	(millions)
Service cost	$	10.5		$	11.3		$	0.7		$	0.8
Interest cost	13.2			12.6			1.5			1.7
Expected return on plan assets	(12.3		)	(12.9		)	(0.8		)	(0.7		)
Prior service cost	0.2			0.2			0.3			0.8
Recognized net actuarial (gain)/loss	13.0			12.8			(0.4		)	—
Net periodic benefit costs before regulatory adjustment	24.6			24.0			1.3			2.6
Regulatory adjustment	(1.0		)	(3.2		)	1.5			1.4
Net periodic benefit costs	$	23.6		$	20.8		$	2.8		$	4.0