Revenue

12 Months Ended

Dec. 31, 2019

Revenue from Contract with Customer [Abstract]

We disaggregate our revenue by geographical region as follows:



	Year ended December 31,
Net Sales	2019		2018		2017
United States	$	1,179.6	$	1,138.6	$	938.4
Iceland	657.0		754.6		650.7
Total	$	1,836.6	$	1,893.2	$	1,589.1

We enter into contracts to sell mainly primary aluminum to our customers. Revenue is recognized when our performance obligations with our customer are satisfied. Our obligations under the contracts are satisfied when we transfer control of our primary aluminum to our customer which is generally upon shipment or delivery to customer directed locations. The amount of consideration we receive, thus the revenue we recognize, is a function of volume delivered, market price of primary aluminum, as determined on the LME, plus regional premiums and any value-added product premiums.

The payment terms and conditions in our contracts vary and are not significant to our revenue. We complete an appropriate credit evaluation for each customer at contract inception. Customer payments are due in arrears and are recognized as accounts receivable - net and due from affiliates in our consolidated balance sheets. Accounts receivable - net decreased $12.4 million from December 31, 2018 to December 31, 2019, due to timing of receivable collections.

In connection with our sales agreement with Glencore, we invoice Glencore prior to physical shipment of goods for a majority of production generated from each of our U.S. domestic smelters. For those sales, revenue is recognized only when Glencore has specifically requested such treatment and has made a commitment to purchase the product. The goods must be complete, ready for shipment and separated from other inventory with control over the goods passing to Glencore. We must retain no further performance obligations.