Plant to be Retired, Net	9 Months Ended
Sep. 30, 2017
Plant to be Retired, Net [Abstract]
Plant to be Retired, Net Disclosure	20. PLANT TO BE RETIRED, NET When Great Plains Energy and KCP&L retire utility plant, the original cost, net of salvage, is charged to accumulated depreciation. However, when it becomes probable an asset will be retired significantly in advance of its original expected useful life and in the near term, the cost of the asset and related accumulated depreciation is recognized as a separate asset as a probable abandonment. If the asset is still in service, the net amount is classified as plant to be retired, net on the consolidated balance sheets. If the asset is no longer in service, the net amount is classified in regulatory assets on the consolidated balance sheets. Great Plains Energy and KCP&L must also assess the probability of full recovery of the remaining net book value of the abandonment. The net book value that may be retained as an asset on the balance sheet for the abandonment is dependent upon amounts that may be recovered through regulated rates, including any return. An impairment charge, if any, would equal the difference between the remaining net book value of the asset and the present value of the future revenues expected from the asset. In June 2017, Great Plains Energy and KCP&L announced the expected retirement of certain older generating units, including GMO's Sibley No. 3 Unit, over the next several years. As of September 30, 2017, Great Plains Energy has determined that Sibley No. 3 Unit meets the criteria to be considered probable of abandonment and has classified its remaining net book value of $146.3 million within plant to be retired, net on its consolidated balance sheet. The Company is currently allowed a full recovery of and a full return on Sibley No. 3 Unit in rates and has concluded that no impairment is required as of September 30, 2017.

20. PLANT TO BE RETIRED, NET

When Great Plains Energy and KCP&L retire utility plant, the original cost, net of salvage, is charged to accumulated depreciation. However, when it becomes probable an asset will be retired significantly in advance of its original expected useful life and in the near term, the cost of the asset and related accumulated depreciation is recognized as a separate asset as a probable abandonment. If the asset is still in service, the net amount is classified as plant to be retired, net on the consolidated balance sheets. If the asset is no longer in service, the net amount is classified in regulatory assets on the consolidated balance sheets.

Great Plains Energy and KCP&L must also assess the probability of full recovery of the remaining net book value of the abandonment. The net book value that may be retained as an asset on the balance sheet for the abandonment is dependent upon amounts that may be recovered through regulated rates, including any return. An impairment charge, if any, would equal the difference between the remaining net book value of the asset and the present value of the future revenues expected from the asset.

In June 2017, Great Plains Energy and KCP&L announced the expected retirement of certain older generating units, including GMO's Sibley No. 3 Unit, over the next several years. As of September 30, 2017, Great Plains Energy has determined that Sibley No. 3 Unit meets the criteria to be considered probable of abandonment and has classified its remaining net book value of $146.3 million within plant to be retired, net on its consolidated balance sheet. The Company is currently allowed a full recovery of and a full return on Sibley No. 3 Unit in rates and has concluded that no impairment is required as of September 30, 2017.