Apparently, after getting all the Terminals in Halo: Combat Evolved Anniversary, you get 100,000 credits rewarded to your Halo: Reach multiplayer profile. I’ve done that, but I haven’t been rewarded that amount.
To get the credits you have to use a code given to you on the 360 Waypoint App. I’m pretty sure the app isn’t available on the Xbox One so you’re going to need a 360 to get to it, and even then I can’t guarantee it will work.
I’m not sure if that’ll work but I’ll try it. Thanks anyway. 
That would be amazing if I could get that high. I’ve got close to 90k but was minipulates into buying packs
Just tried it on the Halo Waypoint app on the Xbox 360. You can enter the codes in for the 10 terminals, but it won’t allow you to put in the code for the 11th terminal, therefore, you can’t get that 100,000 Credits bonus.