Catechism of the Catholic Church §1560 — excerpt
As Christ's vicar, each bishop has the pastoral care of the particular Church entrusted to him, but at the same time he bears collegially with all his brothers in the episcopacy the solicitude for all the Churches: "Though each bishop is the lawful pastor only…
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: Pius XII, Fidei donum: AAS 49 (1957) 237 · LG 23 · CD 4 · 36 · 37 · AG 5 · 6 · 38