We estimate fair value at a price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants in the principal market for the asset or liability. The valuation techniques require inputs that we categorize into a three-level hierarchy, from highest to lowest level of observable inputs, as follows: unadjusted quoted prices for identical assets or liabilities in active markets ("Level 1"); direct or indirect observable inputs, including quoted prices or other market data, for similar assets or liabilities in active markets or identical assets or liabilities in less active markets ("Level 2"); and unobservable inputs that require significant judgment for which there is little or no market data ("Level 3"). When multiple input levels are required for a valuation, we categorize the entire fair value measurement according to the lowest level of input that is significant to the measurement, even though we may have also utilized significant inputs that are more readily observable.

The period-end carrying amounts of cash and cash equivalents, receivables, accounts payable and accrued liabilities approximate their fair values due to the short-term maturities of these financial instruments. As of June 30, 2023 and December 31, 2022, the carrying amounts of our total debt were $601 million and $609 million, respectively, and the estimated fair values were $598 million and $613 million, respectively. The fair value of our debt was estimated based on available market prices for the same or similar instruments that are considered significant other observable inputs (Level 2) within the fair value hierarchy and was based on information available to us as of the respective period end dates.

We determine the fair value of our interest rate swap contract using a forward interest rate curve obtained from a third-party market data provider. The fair value of the contract is the sum of the expected future settlements between the contract counterparties, discounted to present value. The expected future settlements are determined by comparing the contract interest rate to the expected forward interest rate as of each settlement date and applying the difference between these two rates to the notional amount of debt in the interest rate swap contract.

We did not change our valuation techniques for measuring the fair value of any financial assets and liabilities during the six months ended June 30, 2023. Transfers between hierarchy levels, if any, are recognized at the end of the reporting period. There were no transfers between hierarchy levels during the six months ended June 30, 2023.

Our interest rate swap contract is currently our only financial instrument remeasured at fair value on a recurring basis. A summary of the carrying value and fair value of this financial instrument are as follows:



			Estimated Fair Value Measurements
			Quoted		Significant
			Prices		Other		Significant
			in Active		Observable		Unobservable
	Carrying		Markets		Inputs		Inputs
(In millions)	Value		(Level 1)		(Level 2)		(Level 3)
As of June 30, 2023:
Prepaid expenses and other current assets	$	8	$	—	$	8	$	—
Other assets		4		—		4		—
Total assets	$	12	$	—	$	12	$	—

As of December 31, 2022:
Prepaid expenses and other current assets	$	6	$	—	$	6	$	—
Other assets		4		—		4		—
Total assets	$	10	$	—	$	10	$	—