DETROIT — The estate of former Detroit Pistons owner Bill Davidson is challenging the government in U.S. Tax Court over billions of dollars claimed by the IRS.

The Detroit Free Press (http://on.freep.com/12ZhEZC) says the Internal Revenue Service objects to how Davidson's accountants valued stock in his company, Guardian Industries, which makes glass and parts for the auto industry.

Other issues include tens of millions of dollars given to Davidson's wife and money used to help her daughter build a home. The newspaper says the IRS is seeking about $2 billion or more in estate taxes. The agency declined to comment. Davidson's estate challenged the IRS last week in a filing in U.S. Tax Court.

Davidson died in 2009 at age 86.