CTC Credit Amounts

I've read that each child dependent is worth $3600 per child under 6. I would like to know, is this in addition to what I would've gotten back normally? Or is it $3600 total for the year. I'm asking because I share custody with my ex-husband and we are trying to distribute funds fairly. If it's $3600 total, then that's an easy $1800 split. If claiming a child also gives us additional benefits, then I'd like to know what those are so we can calculate fairly (I'm the only one claiming dependents at the moment... it's complicated). I do understand that this is refundable, whereas the typical benefit is an offsetting one. It's great being able to ask these questions. Thanks for your time!