FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2018

Fair value of assets and liabilities measured on a recurring basis, categorized by level within the fair value hierarchy

The following tables summarize our financial assets and liabilities that were accounted for at fair value on a recurring basis, categorized by level within the fair value hierarchy:



	September 30, 2018
(in millions)	Level 1		Level 2		Level 3		Total
Derivative assets
Natural gas contracts	$	1.6	$	—	$	—	$	1.6
FTRs	—		—		5.1		5.1
Coal contracts	—		0.6		—		0.6
Total derivative assets	$	1.6	$	0.6	$	5.1	$	7.3

Derivative liabilities
Natural gas contracts	$	0.6	$	—	$	—	$	0.6



	December 31, 2017
(in millions)	Level 1		Level 2		Level 3		Total
Derivative assets
Natural gas contracts	$	0.8	$	—	$	—	$	0.8
Petroleum product contracts	0.3		—		—		0.3
FTRs	—		—		2.0		2.0
Coal contracts	—		0.4		—		0.4
Total derivative assets	$	1.1	$	0.4	$	2.0	$	3.5

Derivative liabilities
Natural gas contracts	$	2.3	$	—	$	—	$	2.3
Coal contracts	—		0.5		—		0.5
Total derivative liabilities	$	2.3	$	0.5	$	—	$	2.8

Reconciliation of changes in the fair value of items categorized as Level 3 measurements

The following table summarizes the changes to derivatives classified as Level 3 in the fair value hierarchy:



	Three Months Ended September 30						Nine Months Ended September 30
(in millions)	2018			2017			2018			2017
Balance at the beginning of period	$	8.0		$	5.8		$	2.0		$	2.0
Purchases	—			—			9.0			6.9
Settlements	(2.9		)	(2.2		)	(5.9		)	(5.3		)
Balance at the end of period	$	5.1		$	3.6		$	5.1		$	3.6

Schedule of carrying value and estimated fair value of financial instruments not recorded at fair value

The following table shows the financial instruments included on our balance sheets that are not recorded at fair value:



	September 30, 2018				December 31, 2017
(in millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Long-term debt, including current portion	$	1,166.9	$	1,214.1	$	1,166.2	$	1,302.4