PROPERTY, PLANT, AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2014

Property, Plant and Equipment [Abstract]

Schedule of property, plant, and equipment

Property, plant, and equipment consisted of the following utility, nonutility, and nonregulated assets at December 31:

(Millions)	2014		2013
Electric utility	$	3,587.4	$	3,289.2
Natural gas utility	5,811.8		5,428.5
Total utility property, plant, and equipment	9,399.2		8,717.7
Less: Accumulated depreciation	3,185.9		3,073.2
Net	6,213.3		5,644.5
Construction work in progress	351.8		351.5
Plant to be retired, net *	12.5		14.4
Net utility property, plant, and equipment	6,577.6		6,010.4
Nonutility plant	144.6		131.1
Less: Accumulated depreciation	81.1		80.4
Net	63.5		50.7
Construction work in progress	73.9		38.0
Net nonutility property, plant, and equipment	137.4		88.7
PDI energy assets	140.2		109.8
Other nonregulated	33.7		20.7
Total nonregulated property, plant, and equipment	173.9		130.5
Less: Accumulated depreciation	39.5		30.5
Net	134.4		100.0
Construction work in progress	10.4		7.1
Net nonregulated property, plant, and equipment	144.8		107.1
Total property, plant, and equipment	$	6,859.8	$	6,206.2

* In connection with the WPS Consent Decree with the EPA, WPS announced that the Weston 1, Pulliam 5, and Pulliam 6 generating units will be retired early. These units are currently included in rate base, and WPS continues to depreciate them on a straight-line basis using the composite depreciation rates approved by the PSCW. The amount presented above is net of accumulated depreciation. See Note 17, Commitments and Contingencies, for more information regarding the Consent Decree.