This isn't universal, but prepare for a bunch of BS :). The bigger the company the less efficient they need to be to survive. Shenanigans and lazy work are often overlooked as individual contributions matter so little to the overall bottom line. Expect the need to be polite and at the same time tolerant of those who aren't. With big companies you end up with a few people that want white shoe behavior and they'll make a bunch of noise if they don't get it.
That said, it's very difficult to get fired once you settle in. You usually don't have to work too hard or too long. Pay and benefits are comfortable and work is stable if a bit boring or meaningless.
Your job satisfaction depends maybe 90% on your direct manager so make sure you like them during the interview. Your relationship and boss quality will make or break your enjoyment of your job most of the time.