Consolidated Statements of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating Revenues
Electric revenues	$ 857.2	$ 856.8	$ 2,110.5	$ 2,099.7
Operating Expenses
Fuel and purchased power	180.0	184.1	464.0	462.2
Transmission	29.1	23.8	80.4	64.5
Utility operating and maintenance expenses	187.9	193.3	555.0	553.1
Costs to achieve the anticipated merger with Westar Energy, Inc.	(2.4)	14.4	24.4	19.4
Depreciation and amortization	92.7	86.4	277.7	256.9
General taxes	63.5	63.7	176.1	174.5
Other	0.5	9.2	3.1	15.0
Total	551.3	574.9	1,580.7	1,545.6
Operating income	305.9	281.9	529.8	554.1
Other Income and Expenses
Non-operating income	8.1	4.3	27.6	9.7
Non-operating expenses	(20.3)	(3.0)	(27.9)	(10.7)
Loss on Series B Preferred Stock dividend make-whole provisions [Note 12]	(67.7)	0.0	(124.8)	0.0
Loss on extinguishment of debt [Note 11]	(82.8)	0.0	(82.8)	0.0
Total	(162.7)	1.3	(207.9)	(1.0)
Interest charges	(30.9)	(67.6)	(242.8)	(251.7)
Income before income tax expense and income from equity investments	112.3	215.6	79.1	301.4
Income tax expense	(102.3)	(82.7)	(87.2)	(111.5)
Income from equity investments, net of income taxes	0.5	0.7	2.0	2.1
Net income (loss)	10.5	133.6	(6.1)	192.0
Preferred stock dividend requirements and redemption premium	7.1	0.9	37.3	1.7
Earnings (loss) available for common shareholders	$ 3.4	$ 132.7	$ (43.4)	$ 190.3
Average number of basic common shares outstanding	215.6	154.6	215.5	154.5
Average number of diluted common shares outstanding	215.7	154.9	215.5	154.9
Basic and diluted earnings (loss) per common share	$ 0.02	$ 0.86	$ (0.20)	$ 1.23
Cash dividends per common share	$ 0.275	$ 0.2625	$ 0.825	$ 0.7875
Comprehensive Income
Net income (loss)	$ 10.5	$ 133.6	$ (6.1)	$ 192.0
Other comprehensive income
Reclassification to expenses, net of tax	1.3	1.3	4.1	4.1
Derivative hedging activity, net of tax	1.3	1.3	4.1	4.1
Amortization of net losses included in net periodic benefit costs, net of tax	0.1	0.2	0.3	0.4
Change in unrecognized pension expense, net of tax	0.1	0.2	0.3	0.4
Total other comprehensive income	1.4	1.5	4.4	4.5
Comprehensive income (loss)	11.9	135.1	(1.7)	196.5
Kansas City Power and Light Company [Member]
Operating Revenues
Electric revenues	595.7	597.6	1,474.3	1,474.1
Operating Expenses
Fuel and purchased power	124.1	118.5	314.4	298.7
Transmission	19.8	14.5	52.9	44.8
Utility operating and maintenance expenses	125.6	131.9	374.2	379.6
Costs to achieve the anticipated merger with Westar Energy, Inc.	(1.5)	0.0	10.3	0.0
Depreciation and amortization	66.3	61.9	199.9	184.1
General taxes	51.4	51.0	140.2	136.9
Other	0.1	0.6	0.5	2.3
Total	385.8	378.4	1,092.4	1,046.4
Operating income	209.9	219.2	381.9	427.7
Other Income and Expenses
Non-operating income	2.7	3.6	6.9	7.5
Non-operating expenses	(2.0)	(1.9)	(6.4)	(5.6)
Total	0.7	1.7	0.5	1.9
Interest charges	(34.3)	(34.7)	(105.5)	(104.9)
Income before income tax expense and income from equity investments	176.3	186.2	276.9	324.7
Income tax expense	(62.2)	(68.5)	(99.0)	(116.5)
Net income (loss)	114.1	117.7	177.9	208.2
Comprehensive Income
Net income (loss)	114.1	117.7	177.9	208.2
Other comprehensive income
Reclassification to expenses, net of tax	1.2	1.2	3.8	4.0
Derivative hedging activity, net of tax	1.2	1.2	3.8	4.0
Total other comprehensive income	1.2	1.2	3.8	4.0
Comprehensive income (loss)	$ 115.3	$ 118.9	$ 181.7	$ 212.2