First, Marty's comment about the bill being footed by Maryland taxpayers is wrong, but you and others apparently accepted it with any questions. The Federal government is paying to rebuild the bridge since it may take 20 years for all the insurance and other claims to be settled under maritime law.

Here is the post from Larry Perrone whose career was in the insurance business:

The boat’s insurance carrier is only a small piece of the pie.  Maritine law makes every company that had an item in the containers also responsible.  Those companies will pay a pro rata share based on the number and value of the items.  It will probably take 20 years to sort it out.  The insurance money should go back to the federal government if the fed is paying the bills.  The bridge insurer also will pay and get their money back.  There also could be many other carriers involved once they figure out the cause of the ship losing power.  Marine claims are very complicated.