It's an "on paper" accounting ploy. Goodwill is an intangible asset (or liability) of every company. Your airplanes, physical facilities, Accounts Receivable, etc. all have an asset value stated in dollars.
However, when a company is sold, it is (usually) sold for more than the sum of all the tangible assets. The difference between what the tangible assets are worth and the selling price is called goodwill. It's basically stating that the company is worth more than its assets because of its reputation, history, etc.
Under the imprimatur of the Federal Accounting Standards Board (FASB), companies are allowed on their books to assign a dollar value to that goodwill and have it count in the company's total asset value. While the write down of goodwill is never good, in the long run it doesn't really tell you anything about the financial health of the company. For all we know, the write down occurred because the current management wishes to be honest and they want to restate some inflated goodwill value that a previous management set.
However, to keep posting that Dl lost $6 billion dollars in the first quarter is an indication of the poster's ignorance of accounting and finance. DL lost $274 million in the first quarter. That is the figure to be concerned with. And, compared to my company (AMR) and UA, DL didn't do too badly.
