Risk assessment companies estimated insured losses from Wilma at $6 billion to $10 billion in Florida.
Wilma smashed into southwestern Florida on Monday as a surprisingly strong Category 3 hurricane after feeding for days over the warm waters of the Gulf of Mexico and killing 17 people in a rampage through the Caribbean.
Four deaths were confirmed in Florida, including a man who died when a tree fell on him in the Fort Lauderdale suburb of Coral Springs. Two people died in Collier County in southwest Florida and one in St Johns County in northeast Florida.
State officials said 3.1 million households, or more than 6 million people, were without electricity.
Wilma flooded parts of the Overseas Highway linking the Keys with the mainland. Emergency officials in Marathon, in the middle of the 175km island chain, reported residents stranded on roofs by flooding and said leaking propane tanks and gas lines had caused small explosions.
The hurricane buried coastal roads in sand, blasted windows out of high-rise buildings, demolished mobile homes, flipped cars and felled trees in the Miami-Fort Lauderdale area.
Wilma was the eighth hurricane
to hit Florida in 15 months
Several hospitals were damaged or lost power. At least three evacuated some patients after the storm passed, including 36 newborns from West Boca Hospital in Palm Beach County.
Wilma, a sprawling hurricane that covered much of Florida, was the eighth hurricane to strike the state in 15 months.
More than 3100 National Guard troops were deployed and another 3500 were on alert. A handful of looting arrests were reported and many cities imposed overnight curfews.
Wilma had weakened after three days hammering Cancun and Cozumel in Mexico, where it battered the tourism industry, but revved up to reach Florida with 200kph winds.
They slowed to 165kph during Wilma's furious four-hour trek across Florida then strengthened again to race northeast across the Atlantic with 195kph winds.
Forecasters said Wilma could be the strongest storm in the Miami area since August 1992, when Hurricane Andrew caused more than $25 billion in damage.
US President George Bush signed a major disaster declaration for Florida and promised the federal authorities would work closely with local officials to distribute food, medicine, water and communications equipment.