GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2014

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of identifiable intangible assets other than goodwill

Our intangible assets listed below consist of contractual service agreements that provide for major maintenance and protection against unforeseen maintenance costs related to the combustion turbine generators at the Fox Energy Center. These contractual service agreements are included in other long-term assets on the balance sheets.

	December 31, 2014							December 31, 2013
(Millions)	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Amortized intangible assets
Contractual service agreements	$	15.6	$	(4.3	)	$	11.3	$	15.6	$	(1.8	)	$	13.8

Schedule of intangible asset amortization expense

The table below shows the amortization recorded during the years ended December 31:

(Millions)	2014		2013
Amortization recorded in depreciation and amortization expense	$	2.2	$	1.8
Amortization recorded in regulatory assets	0.3		—

Schedule of intangible asset amortization expense for the next five years

Amortization for the next five years is estimated to be:

	For the Year Ending December 31
(Millions)	2015		2016		2017		2018		2019
Amortization to be recorded in depreciation and amortization expense	$	2.2	$	2.2	$	1.7	$	1.2	$	1.2
Amortization to be recorded in regulatory assets	1.0		1.0		0.5		—		—