According to CEF, CAE and CPE are the highest level possible. If I apply to some top US university/college, will they accept a certificate from Cambridge instead of TOEFL?
You should read the minimum requirements of the program at the university to which you are applying. Some universities only accept TOEFL, some other only accept IELTS, some universities accept both of these, and some universities accept those certificates like FCE, CAE or CPE as well as TOEFL or IELTS. (Some other universities also accept the English tests which are designed by themselves.)
I have seen some tables in which the minimum scores of each test is mentioned. For instance a university may accept a 7.0 of IELTS, 100 iBT (internet based TOEFL) and an A of FCE.
So the only advice I can give you is to check the minimum English language requirements of the university and the program you are applying.