Is Two-Factor Authentication Secure?

Nowadays a lot of companies are implementing two factor authentication to protect accounts such as Google, Steam, and Apple. But is it as secure as they say it is. Does anyone know a way to intercept the codes sent from the texts or with the apps. I guess you could if you infected the phone but has anyone heard of any other way besides that. I am asking for myself because I always implement it on my accounts if its offered but I was wondering if it was smoke and mirrors to give a false sense of security or actually a viable security measure.

Thanks

Plague_