Community property is a difficult concept to understand. Just because something is brought into the marriage does not mean that it will always completely remain separate property. The interest that accrues on a separate property asset is community property.
When there are large marital estates, many times community assets and separate property have become co-mingled over the years. Sometimes those issues and ambiguities can be resolved through Alternative Dispute Resolution or mediation. However, a lot of times those issues cannot be resolved amicably. An experienced trial lawyer who is both comfortable and confident in the courtroom is absolutely critical.
With large marital estates
there are often pre-nuptial agreements and post-nuptial agreements that are contested. These contractual disputes are often litigated in divorce court