Is 75 mins enough transfer time from international to domestic at JFK

I did a similar connection today, flying in from the EU to terminal 4 and connecting to a domestic flight in Terminal 2. I had almost perfect conditions to help me:

1. No checked in luggage
2. Global Entry
3. CLEAR (normally also precheck but somehow it didn’t get added this time)
4. Same ticket

Between the time I exited the doors of the plane and the time I was at my gate it took 40 minutes:

1. 5 minutes to walk to immigration
2. 3 minutes for Global Entry
3. 10 minutes to take Airtrain to Terminal 2
4. 10 minutes to go through security with CLEAR (might’ve potentially been 5 if I also had precheck)
5. 5 minutes to reach gate

So a total of ~35 minutes. But given that your plane might also be delayed (mine was) or forced to wait for a free jet bridge (mine was for 15 minutes), I’d say don’t book inbound international connections under 1,5 hours via JFK if you’re not willing to risk missing your flight. If you don’t have Global Entry add another 60-120 minutes on top of that. If you don’t have CLEAR or Precheck, add another 20 on top.

In the end despite my best efforts I ended up missing the flight, which got me a free hotel room and meal vouchers from Delta.

Very possibly no. I wouldn't chance it. The key question is whether you booked both legs in one ticket, or separately.

Success depends on lots of factors, among them:

1. Will the incoming flight land on time? Delays are not uncommon.
2. What's the load in the airport? Immigration and security could be a metter of 15 minutes or 2 hours.
3. Do you have luggage? Waiting for it can take 5 minutes or 30 (or more).
4. Can you take a shorter line? USA citizens wait less than foreigners, having Global Entry or TSA-Pre helps.

With one ticket:

1. The airline sold it to you, so they believe you'll probably make it. They know better than me.
2. If you don't make it (happens, happened to me), they'll rebook you on the next flight and give you a hotel if needed. Annoying, but at least you're not paying.

With two tickets:

1. You can buy arbitrarily short connections, even one minute. It's on you.
2. If you're late, you're considered no-show on the next flight. The airline doesn't care why you're late (even if the first leg was their own flight).
3. You need to buy a new ticket to your final destination. If a hotel is needed, you pay for it.
4. If the second leg is booked along with more tickets (e.g. a DTW-JFK return), they're all cancelled.

Ouch.

If you have kids in tow, checked luggage and no Global Entry, I give it less than 25% chance of success. If everything works perfect, you can make it, but the slightest hiccup will make you miss it.

It would help if you post your full itinerary so we can assess wait times and terminal transfer times.

It looks last the flight for JFK->DTW on Delta is DL 5074 departing at 5:55pm. If you miss that there is a Jet Blue flight leaving at 8:55pm and you have a very good chance of making this.

It's unlikely that Delta (or whoever your marketing carrier is) would rebook you on JetBlue since it's not a SkyTeam partner. You have a few choices here

1. Call the airline that issued your ticket and ask them if they would rebook to JetBlue if you miss the connection.
2. Buy the JetBlue tickets up front as "insurance" . Current prices start at $200 per person
3. Chance it. Try to buy JetBlue after you missed your connection, but it may be sold out or very expensive as a last minute ticket.
4. Risk spending the night in NY. The marketing carrier may give you a hotel and/or food voucher but it's not guaranteed and it's also possible that many hotels are sold out or very expensive on New Years eve.

All of this is only relevant if you bought this trip as a single ticket (which I can't really reproduce). My best guess it's Virgin Atlantic 127 (code shared with Delta, KLM & Air France) but that comes in at 4:10p and you would have 105 minutes, not 75. 20 extra minutes would greatly increase your chance of making it!

If these are two separate tickets: DO NOT BUY the delta ticket, buy the JetBlue ticket instead.