Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

The following table shows our derivative assets and derivative liabilities:



	December 31, 2017				December 31, 2016
(in millions)	Derivative Assets		Derivative Liabilities		Derivative Assets		Derivative Liabilities
Other current
Natural gas contracts	$	5.6	$	9.4	$	31.4	$	0.4
Petroleum products contracts	1.2		—		0.2		0.1
FTRs	4.4		—		5.1		—
Coal contracts	0.6		0.6		1.5		1.4
Total other current	$	11.8	$	10.0	$	38.2	$	1.9

Other long-term
Natural gas contracts	$	0.1	$	1.4	$	2.9	$	—
Coal contracts	0.5		0.2		0.5		0.5
Total other long-term	$	0.6	$	1.6	$	3.4	$	0.5
Total	$	12.4	$	11.6	$	41.6	$	2.4

Estimated notional volumes and realized gain (losses)

Our estimated notional sales volumes and realized gains (losses) were as follows for the years ended:



	December 31, 2017				December 31, 2016				December 31, 2015
(in millions)	Volume	Gains (Losses)			Volume	Gains (Losses)			Volume	Gains (losses)
Natural gas contracts	123.1 Dth	$	(8.0	)	151.1 Dth	$	(59.6	)	86.2 Dth	$	(50.5	)
Petroleum products contracts	18.0 gallons	(1.3		)	14.7 gallons	(3.2		)	7.8 gallons	(1.9		)
FTRs	36.2 MWh	14.0			33.7 MWh	13.3			27.3 MWh	6.7
Total		$	4.7			$	(49.5	)		$	(45.7	)

Offsetting Assets and Liabilities

The following table shows derivative assets and derivative liabilities if derivative instruments by counterparty were presented net on our balance sheets:



	December 31, 2017							December 31, 2016
(in millions)	Derivative Assets			Derivative Liabilities				Derivative Assets				Derivative Liabilities
Gross amount recognized on the balance sheet	$	12.4		$	11.6			$	41.6			$	2.4
Gross amount not offset on the balance sheet	(4.9		)	(9.0		)	⁽¹⁾	(4.9		)	⁽²⁾	(0.5		)
Net amount	$	7.5		$	2.6			$	36.7			$	1.9


⁽¹⁾	Includes cash collateral posted of $4.1 million.


⁽²⁾	Includes cash collateral received of $4.4 million.