The Quran states it is complete, perfect and fully detailed:
6:19: *Say, “Whose testimony is the greatest?” Say, “GOD’s. He is the witness between me and you that this Quran has been inspired to me, to preach it to you and whomever it reaches. Indeed, you bear witness that there are other gods beside GOD.” Say, “I do not testify as you do; there is only one god, and I disown your idolatry.” *
6:38: All the creatures on earth, and all the birds that fly with wings, are communities like you. We did not leave anything out of this book*. To their Lord, all these creatures will be summoned. *
6:114: Shall I seek other than GOD as a source of law, when He has revealed to you this book fully detailed? Those who received the scripture recognize that it has been revealed from your Lord, truthfully. You shall not harbor any doubt. *
6:115: *The word of your Lord is complete, in truth and justice. Nothing shall abrogate His words. He is the Hearer, the Omniscient. *
50:45: We are fully aware of everything they utter, while you have no power over them. Therefore, remind with this Quran, those who reverence My warnings.
It futher states that religious regulatoins NOT in the Quran constitute a religion other than Islam:
42:21: *They follow idols who decree for them religious laws never authorized by GOD. If it were not for the predetermined decision, they would have been judged immediately. Indeed, the transgressors have incurred a painful retribution. *
17:46: We place shields around their minds, to prevent them from understanding it, and deafness in their ears. And when you preach your Lord, using the Quran alone, they run away in aversion.