Since we have NO federally-mandated paid parental leave in the US, your husband would have paid leave for paternity only if his employer chooses to provide it. Most women end up with 6 weeks of paid maternity leave because delivery and recovery from it are considered medical conditions (short-term medical disability) and therefore health insurance plans pay one's salary for that time. The father (or adoptive parents) don't qualify for that paid leave. Federal law does require that employers with over 50 employees (I think) allow employees to take up to 12 weeks of UNPAID leave without fear of being fired. As someone else said, you'll want to look up FMLA to get the exact information. It might be worth seeing if CA has some kind of legislation regarding paid parental leave. Also, your husband will need to talk to his employer's Human Resources folks to get clear on the company's policies. Good luck, and it's wonderful that your husband IS going to take paternity leave. Too few fathers do!
[ETA: It's sooo cool to hear that CA does have paid parental leave. Ignore everything I typed, except the last sentence.]