Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income	$ 524.9	$ 300.2
Adjustments to reconcile income to net cash from operating activities:
Depreciation and amortization	411.6	277.3
Amortization of nuclear fuel	28.6	24.2
Amortization of deferred refueling outage	14.7	12.1
Amortization of deferred regulatory gain from sale leaseback	(4.1)	(4.1)
Amortization of corporate-owned life insurance	17.2	15.7
Non-cash compensation	25.2	6.7
Net deferred income taxes and credits	47.8	127.0
Allowance for equity funds used during construction	(2.4)	(1.1)
Payments for asset retirement obligations	(15.9)	(1.9)
Equity in earnings of equity method investees, net of income taxes	(4.7)	(4.9)
Other	(1.9)	(5.3)
Changes in working capital items:
Accounts receivable	(34.9)	(19.7)
Accounts receivable pledged as collateral	(15.0)	0.0
Fuel inventory and supplies	44.6	15.5
Prepaid expenses and other current assets	(3.4)	55.5
Accounts payable	(58.5)	(10.0)
Accrued taxes	119.0	35.6
Other current liabilities	38.9	(108.5)
Changes in other assets	26.0	22.9
Changes in other liabilities	33.9	5.5
Cash Flows from Operating Activities	1,191.6	742.7
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Additions to property, plant and equipment	(698.3)	(564.6)
Cash acquired from the merger with Great Plains Energy	1,154.2	0.0
Purchase of securities - trusts	(107.0)	(15.3)
Sale of securities - trusts	110.2	15.9
Investment in corporate-owned life insurance	(16.2)	(16.2)
Proceeds from investment in corporate-owned life insurance	6.5	2.1
Proceeds from settlement of interest rate swap	140.6	0.0
Other investing activities	(15.2)	(3.3)
Cash Flows from (used in) Investing Activities	574.8	(581.4)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Short term debt, net	(166.7)	(177.7)
Collateralized short-term borrowings, net	15.0	0.0
Proceeds from long-term debt	22.9	296.2
Retirements of long-term debt	(127.4)	(125.0)
Retirements of Long Term Debt Of VIEs	(28.5)	(26.8)
Repayment of capital leases	(2.9)	(2.6)
Borrowings against cash surrender value of corporate-owned life insurance	55.1	53.4
Repayment of borrowings against cash surrender value of corporate-owned life insurance	(3.9)	0.0
Distributions to shareholders of noncontrolling interests	0.0	(5.8)
Cash dividends paid	(350.4)	(166.3)
Repurchase of common stock	(486.1)	0.0
Other financing activities	(17.2)	(6.4)
Cash Flows (used in) Financing Activities	(1,090.1)	(161.0)
NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	676.3	0.3
CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of period	3.5	3.2
End of period	679.8	3.5
Westar Energy Inc [Member]
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income	318.5	300.2
Adjustments to reconcile income to net cash from operating activities:
Depreciation and amortization	281.6	277.3
Amortization of nuclear fuel	18.6	24.2
Amortization of deferred refueling outage	10.5	12.1
Amortization of deferred regulatory gain from sale leaseback	(4.1)	(4.1)
Amortization of corporate-owned life insurance	17.2	15.7
Non-cash compensation	19.9	6.7
Net deferred income taxes and credits	(34.2)	127.0
Allowance for equity funds used during construction	(2.4)	(1.1)
Payments for asset retirement obligations	(10.6)	(1.9)
Equity in earnings of equity method investees, net of income taxes	(3.7)	(4.9)
Other	(1.9)	(5.3)
Changes in working capital items:
Accounts receivable	(50.6)	(19.7)
Fuel inventory and supplies	25.4	15.5
Prepaid expenses and other current assets	(7.0)	55.5
Accounts payable	36.2	(10.0)
Accrued taxes	74.4	35.6
Other current liabilities	23.2	(108.5)
Changes in other assets	22.9	22.9
Changes in other liabilities	(26.7)	5.5
Cash Flows from Operating Activities	707.2	742.7
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Additions to property, plant and equipment	(510.3)	(564.6)
Purchase of securities - trusts	(96.1)	(15.3)
Sale of securities - trusts	101.2	15.9
Investment in corporate-owned life insurance	(16.2)	(16.2)
Proceeds from investment in corporate-owned life insurance	6.5	2.1
Other investing activities	(8.1)	(3.3)
Cash Flows from (used in) Investing Activities	(523.0)	(581.4)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Short term debt, net	48.3	(177.7)
Proceeds from long-term debt	0.0	296.2
Retirements of long-term debt	0.0	(125.0)
Retirements of Long Term Debt Of VIEs	(28.5)	(26.8)
Repayment of capital leases	(2.9)	(2.6)
Borrowings against cash surrender value of corporate-owned life insurance	55.1	53.4
Repayment of borrowings against cash surrender value of corporate-owned life insurance	(3.9)	0.0
Distributions to shareholders of noncontrolling interests	0.0	(5.8)
Cash dividends paid	(235.1)	(166.3)
Other financing activities	(17.3)	(6.4)
Cash Flows (used in) Financing Activities	(184.3)	(161.0)
NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(0.1)	0.3
CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of period	3.5	3.2
End of period	3.4	3.5
KCPL [Member]
CASH FLOWS FROM (USED IN) OPERATING ACTIVITIES:
Net income	165.1	177.9
Adjustments to reconcile income to net cash from operating activities:
Depreciation and amortization	209.0	199.9
Amortization of nuclear fuel	18.7	24.1
Amortization of deferred refueling outage	10.3	13.7
Net deferred income taxes and credits	25.2	32.6
Allowance for equity funds used during construction	(1.2)	(3.4)
Payments for asset retirement obligations	(9.9)	(14.9)
Other	2.7	6.3
Changes in working capital items:
Accounts receivable	(41.0)	(19.5)
Accounts receivable pledged as collateral	0.0	(20.0)
Fuel inventory and supplies	13.2	3.6
Prepaid expenses and other current assets	(3.6)	8.9
Accounts payable	(97.7)	(75.1)
Accrued taxes	97.9	122.7
Other current liabilities	8.5	9.9
Changes in other assets	28.3	52.6
Changes in other liabilities	79.0	7.3
Cash Flows from Operating Activities	504.5	526.6
CASH FLOWS FROM (USED IN) INVESTING ACTIVITIES:
Additions to property, plant and equipment	(310.6)	(317.1)
Purchase of securities - trusts	(27.9)	(23.8)
Sale of securities - trusts	22.5	21.3
Other investing activities	3.4	0.8
Cash Flows from (used in) Investing Activities	(312.6)	(318.8)
CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES:
Short term debt, net	40.3	(60.9)
Collateralized short-term borrowings, net	0.0	20.0
Proceeds from long-term debt	319.5	296.2
Retirements of long-term debt	(373.4)	(281.0)
Cash dividends paid	(180.0)	(182.0)
Other financing activities	2.9	0.0
Cash Flows (used in) Financing Activities	(190.7)	(207.7)
NET CHANGE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	1.2	0.1
CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Beginning of period	2.2	4.5
End of period	$ 3.4	$ 4.6