DERIVATIVE INSTRUMENTS

The following table shows our derivative assets and derivative liabilities, none of which are designated as hedging instruments.



	December 31, 2018				December 31, 2017
(in millions)	Derivative Assets		Derivative Liabilities		Derivative Assets		Derivative Liabilities
Other current
Natural gas contracts	$	0.8	$	1.0	$	0.8	$	1.9
Petroleum products contracts	—		—		0.3		—
FTRs	3.0		—		2.0		—
Coal contracts	0.2		—		—		0.5
Total other current	$	4.0	$	1.0	$	3.1	$	2.4

Other long-term
Natural gas contracts	$	—	$	0.1	$	—	$	0.4
Coal contracts	0.2		—		0.4		—
Total other long-term	$	0.2	$	0.1	$	0.4	$	0.4
Total	$	4.2	$	1.1	$	3.5	$	2.8

Realized gains (losses) on derivatives are primarily recorded in cost of sales on the income statements. Our estimated notional sales volumes and realized gains (losses) were as follows:



	December 31, 2018			December 31, 2017				December 31, 2016
(in millions)	Volume	Gains		Volume	Gains (Losses)			Volume	Gains (Losses)
Natural gas contracts	38.4 Dth	$	5.1	18.6 Dth	$	(2.4	)	28.6 Dth	$	(1.4	)
Petroleum products contracts	1.8 gallons	0.4		1.3 gallons	0.1			4.4 gallons	(0.6		)
FTRs	9.3 MWh	12.5		9.1 MWh	6.4			8.4 MWh	6.0
Total		$	18.0		$	4.1			$	4.0

At December 31, 2018 and 2017, we had posted cash collateral of $0.5 million and $4.9 million, respectively, in our margin accounts.

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



	December 31, 2018							December 31, 2017
(in millions)	Derivative Assets			Derivative Liabilities				Derivative Assets			Derivative Liabilities
Gross amount recognized on the balance sheet	$	4.2		$	1.1			$	3.5		$	2.8
Gross amount not offset on the balance sheet	(0.8		)	(1.1		)	⁽¹⁾	(1.1		)	(2.3		)	⁽²⁾
Net amount	$	3.4		$	—			$	2.4		$	0.5


⁽¹⁾	Includes cash collateral posted of $0.3 million.


⁽²⁾	Includes cash collateral posted of $1.2 million.