Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair value of assets and liabilities measured on recurring basis, 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:



	December 31, 2016
(in millions)	Level 1		Level 2		Level 3		Total
Derivative assets
Natural gas contracts	$	6.0	$	0.8	$	—	$	6.8
Petroleum products contracts	0.2		—		—		0.2
FTRs	—		—		3.1		3.1
Coal contracts	—		1.9		—		1.9
Total derivative assets	$	6.2	$	2.7	$	3.1	$	12.0

Derivative liabilities
Natural gas contracts	$	0.1	$	—	$	—	$	0.1
Petroleum products contracts	0.1		—		—		0.1
Coal contracts	—		0.5		—		0.5
Total derivative liabilities	$	0.2	$	0.5	$	—	$	0.7



	December 31, 2015
(in millions)	Level 1		Level 2		Level 3		Total
Derivative assets
Natural gas contracts	$	0.5	$	—	$	—	$	0.5
Petroleum products contracts	1.2		—		—		1.2
FTRs	—		—		1.6		1.6
Coal contracts	—		2.0		—		2.0
Total derivative assets	$	1.7	$	2.0	$	1.6	$	5.3

Derivative liabilities
Natural gas contracts	$	9.2	$	0.2	$	—	$	9.4
Petroleum products contracts	4.4		—		—		4.4
Coal contracts	—		7.6		—		7.6
Total derivative liabilities	$	13.6	$	7.8	$	—	$	21.4

Reconcilation of changes in the FV of items categorized as level 3 measurements

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



(in millions)	2016			2015			2014
Balance at the beginning of the period	$	1.6		$	7.0		$	3.5
Purchases	8.1			3.9			15.6
Settlements	(6.6		)	(9.3		)	(12.1		)
Balance at the end of the period	$	3.1		$	1.6		$	7.0

Carrying amount and estimated fair value of certain financial instruments

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



	December 31, 2016				December 31, 2015
(in millions)	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Preferred stock	$	30.4	$	28.8	$	30.4	$	27.3
Long-term debt	2,661.1		2,923.4		2,658.8		2,888.2