Summary of Significant Accounting Policies Subsequent Events (Details) - Subsequent Event [Member]	1 Months Ended
Aug. 31, 2016 $ / shares
Kansas City Power and Light Company [Member]
Dividends Declared [Abstract]
Dividends Payable, Date Declared, Month and Year	2016-08
Dividends Payable, Amount Per Share	$ 55,000,000
Dividends Payable, Date to be Paid	Sep. 19, 2016
Common Stock [Member]
Dividends Declared [Abstract]
Dividends Payable, Date Declared, Month and Year	2016-08
Dividends Payable, Amount Per Share	$ 0.2625
Dividends Payable, Date to be Paid	Sep. 20, 2016
Dividends Payable, Date of Record	Aug. 29, 2016

Date the declared dividend will be paid, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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The month and year (YYYY-MM) that the dividend to be paid was declared.

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Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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