superminister
noun
su·per·min·is·ter ˌsü-pər-ˈmi-nə-stər 
variants or super-minister
plural superministers or super-ministers
: a government minister who has authority over other ministers or departments
… indicated that he has overall coordinating responsibilities as a sort of superminister for economic affairs.
Richard Holbrooke
Richard Holbrooke[Narenda] Modi [prime minister of India] said he would appoint super-ministers to make ministries coordinate better. Reuters
Reuters
Word History
First Known Use
1854, in the meaning defined above