Every state has different law on this issue. If the property is jointly held, it gets equitably divided. Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, and Wisconsin are community property states. In general, this means that property either spouse owned before marriage and the income it has produced are separate property. So are separate gifts, inheritance, property accumulated after separation.
Property accumulated during marriage is to be split equally.
Typically, the two assets that receive the most attention in divorce are the house and the retirement plans. It's also not unusual for divorcing couples to spend a lot of time and money arguing over a particular piece of furniture or a particular gift in the household, because one or both of the parties have tremendous emotional energy tied up in them. In many states, it's not unusual for a judge to give the house to the party who's going to have custody of the children, even if that results in an uneven allocation of value. Judges get creative when it comes to houses. Retirement plans are another issue that generates tension, because the spouse who owns the retirement plan typically doesn't have any idea that the plan might be marital property and available for sharing with his or her spouse.