Hard to say for certain. Companies that size often have many very independent operations run by separate internal departments. I have worked places with internal, AWS and Azure operations underway.
Where I am various parts of the business run workloads on AWS, Google Cloud, and Azure. To some extent I think this sort of behaviour is encouraged by large corporates because it makes contract negotiations easier if you're able to wave in the direction of the other cloud providers you're using and suggest it wouldn't be too hard to migrate over to them.
