FAIR VALUE MEASUREMENTS

We segregate the inputs used in measuring fair value into three levels: Level 1, defined as observable inputs such as quoted prices for identical assets or liabilities in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities in active markets or quoted prices for identical assets or liabilities in markets that are not active; and Level 3, defined as unobservable inputs for which little or no market data exists. We consider counterparty credit risk and our own credit risk in the determination of all estimated fair values.

Recurring Fair Value Measurements

The following assets and liabilities are measured at fair value on a recurring basis:



	December 31, 2015
	Level 1			Level 2			Level 3			Total
	(Thousands of Dollars)
Assets:
Other current assets:
Product imbalances	$	179		$	—		$	—		$	179
Commodity derivatives	11,325			77			—			11,402
Other long-term assets, net:
Interest rate swaps	—			2,755			—			2,755
Total	$	11,504		$	2,832		$	—		$	14,336
Liabilities:
Accrued liabilities:
Product imbalances	$	(419	)	$	—		$	—		$	(419	)
Commodity derivatives	—			(120		)	—			(120		)
Other long-term liabilities:
Guarantee liability	—			—			(1,697		)	(1,697		)
Interest rate swaps	—			(1,452		)	—			(1,452		)
Total	$	(419	)	$	(1,572	)	$	(1,697	)	$	(3,688	)



	December 31, 2014
	Level 1			Level 2			Level 3			Total
	(Thousands of Dollars)
Assets:
Other current assets:
Product imbalances	$	117		$	—		$	—		$	117
Commodity derivatives	11,009			5,353			—			16,362
Total	$	11,126		$	5,353		$	—		$	16,479
Liabilities:
Accrued liabilities:
Product imbalances	$	(1,388	)	$	—		$	—		$	(1,388	)
Commodity derivatives	—			(4,623		)	—			(4,623		)
Other long-term liabilities:
Guarantee liability	—			—			(580		)	(580		)
Total	$	(1,388	)	$	(4,623	)	$	(580	)	$	(6,591	)

Product Imbalances. We value our assets and liabilities related to product imbalances using quoted market prices in active markets as of the reporting date. Therefore, we include these product imbalances in Level 1 of the fair value hierarchy.

Interest Rate Swaps. We estimate the fair value of our forward-starting interest rate swaps using discounted cash flows, which use observable inputs such as time to maturity and market interest rates. Therefore, we include these interest rate swaps in Level 2 of the fair value hierarchy.

Commodity Derivatives. We base the fair value of certain of our commodity derivative instruments on quoted prices on an exchange; accordingly, we include these in Level 1 of the fair value hierarchy. We also have derivative instruments for which we determine fair value using industry pricing services and other observable inputs, such as quoted prices on an exchange for similar derivative instruments. Therefore, we include these derivative instruments in Level 2 of the fair value hierarchy. See Note 17 for a discussion of our derivative instruments.

Guarantees. As of December 31, 2015 and 2014, we recorded a liability of $1.7 million and $0.6 million, respectively, representing the fair value of guarantees we have issued on behalf of Axeon. We estimated the fair value considering the probability of default by Axeon and an estimate of the amount we would be obligated to pay under the guarantees at the time of default. We calculated the fair value based on the guarantees outstanding as of December 31, 2015 and 2014, totaling $71.9 million and $25.3 million, respectively, plus two guarantees that do not specify a maximum amount. We provide guarantees for commodity purchases, lease obligations and certain utilities for Axeon. A majority of these guarantees have no expiration date. Our estimate of the fair value is based on significant inputs not observable in the market and thus falls within Level 3 of the fair value hierarchy.

The following table summarizes the activity in our Level 3 liabilities:



	Year Ended December 31, 2015
	(Thousands of Dollars)
Beginning balance	$	580
Adjustment to guarantee liability	1,117
Ending balance	$	1,697

Fair Value of Financial Instruments

We recognize cash equivalents, receivables, note receivables, payables and debt in our consolidated balance sheets at their carrying amounts. The fair values of these financial instruments, except for the Axeon Term Loan and long-term debt, approximate their carrying amounts.

The estimated fair values and carrying amounts of the long-term debt and the Axeon Term Loan were as follows:



	December 31, 2015				December 31, 2014
	Fair Value		Carrying Amount		Fair Value		Carrying Amount
	(Thousands of Dollars)
Long-term debt	$	2,929,438	$	3,079,349	$	2,764,242	$	2,749,452
Axeon Term Loan	$	172,123	$	170,352	$	164,386	$	169,235

We estimated the fair value of our publicly-traded senior notes based upon quoted prices in active markets; therefore, we determined the fair value of our publicly-traded senior notes falls in Level 1 of the fair value hierarchy. For our other debt, for which a quoted market price is not available, we estimated the fair value using a discounted cash flow analysis using current incremental borrowing rates for similar types of borrowing arrangements and determined the fair value falls in Level 2 of the fair value hierarchy.

We estimated the fair value of the Axeon Term Loan using discounted cash flows, which use observable inputs such as time to maturity and market interest rates, and determined the fair value falls in Level 2 of the fair value hierarchy. The carrying value of the Axeon Term Loan is included in “Other long-term assets, net” on the consolidated balance sheets.