REGULATORY MATTERS (Tables)

3 Months Ended

Mar. 31, 2016

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Changes in Net Regulatory Asset Balance

	For the three months ended March 31,
	2016			2015
	(in millions)
Net regulatory asset balance at beginning of period	$	29.9		$	6.0
Current period (over)/under recovery revenue adjustments		7.7			(9.1	)
Amortization of prior year regulatory asset		(6.4	)		(3.7	)
Net regulatory asset (liability) balance at end of period	$	31.2		$	(6.8	)