GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)

9 Months Ended

Sep. 30, 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 were included in other long-term assets on the balance sheets.

	September 30, 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	$	(3.5	)	$	12.1	$	15.6	$	(1.8	)	$	13.8

Schedule of intangible asset amortization expense

The table below shows our amortization expense recognized in the statements of income:

	Three Months Ended September 30				Nine Months Ended September 30
(Millions)	2014		2013		2014		2013
Amortization recorded in depreciation and amortization expense	$	0.5	$	0.6	$	1.7	$	1.2

Schedule of intangible asset amortization expense for the next five years

The following table shows our estimated amortization expense for the next five years, including amounts recorded through September 30, 2014:

	For the Year Ending December 31
(Millions)	2014		2015		2016		2017		2018
Amortization to be recorded in depreciation and amortization expense	$	2.2	$	2.2	$	2.2	$	1.7	$	1.2
Amortization to be recorded in regulatory assets	0.3		1.0		1.0		0.5		—