I'm not sure Delaware know how to negotiate
"Altaba offered $1.5bn"
then some time later -
"As such, it asks the court in Delaware to “render judgment in favor of the US and against Altaba for the 2016 through 2019 income tax liabilities set forth above, in the amount of $1,091,764,855.”"
So Delaware were offered $1.5bn (of the $2.88bn they wanted at that point) and after years of expensive lawyers they've managed to bargain it down to only asking for just over $1bn. I wish my ex-wife's lawyers were that good