Ugh - the first time that happens, it's always so awful. I guess the first thing to do is to check your assumptions at the door, and realize that most kids do it at some point. Yes, he always said it was stupid, but he (and you) have learned a powerful lesson about curiosity and peer pressure and teen judgment.
I agree with taking away the phone and grounding him - the point you should make is that he has demonstrated his immaturity and poor judgment, and therefore he sacrifices the privileges of maturity and good judgment.
I think it's also a good time to discuss how he got the alcohol and (more importantly) how he got home. Was he driven by someone impaired? How many kids were involved, and what was the risk of alcohol poisoning if any of them went to sleep or passed out?
Google "teen contracts" and that sort of thing, and look at many agreements that can be spelled out between parent and child. What you want is an arrangement whereby your teen can call you at any time, day or night, to tell you he needs to be picked up or extricated from a difficult situation (whether he is impaired or others are). The essential element is that, if he calls you, there is no arguing and no yelling and no imposition of penalties -- it's a "no questions asked" deal. There is also a code word or phrase you can use so that your child doesn't have to say anything in front of his friends, and he can blame you as "the bad guys" for picking him up or making him come home. That lets him save face, and also be safe. Very important. I'd spend the next 2 weeks working on that with your husband, and present it to him with the lifting of sanctions. You both sign it.
Also find out what the policies and penalties are at his high school for kids engaging in these behaviors. Many kids get kicked off teams and so on. There's also some role for education about alcohol poisoning, safety techniques, and the development of the adolescent brain. Sometimes that's better done by school resource officers than
Once the 2 week period is up (or whatever you decide), you can start to ease up the restrictions even if you don't lift them entirely. Some people also let kids earn back their privileges through hard work as well as demonstration of greater maturity and recognition of what he did wrong. Moaning or whining or door slamming shows immaturity and all lengthen the punishment.
Good luck - overall, use it as a learning experience for him but also a bonding experience for you all, rather than just an imposition of dictatorial decrees (which is absolutely how you feel at this point but which won't be successful overall).