One must specify the cheyt; these are the words of Rabbi Yehuda ben Baterah, as it is written (Exodus 32): Oh, this people has sinned a great sin....

Rabbi Akiva says: One does not need to. 

(2) [The High Priest] would come to the goat for Azazel and place his two hands on it, and confess. And this is what he would say: "Please God, we, Your people the House of Israel, have committed wrongdoing, transgressed, and sinned before You. Please God, please forgive the wrongdoing, transgressions and sins that we, Your people the House of Israel, have committed, transgressed, and sinned before You. As it is written in the Torah of Moses Your servant (Leviticus 16:30), 'On this day, you will be forgiven and cleansed from all your sins—before Adonai you will be cleansed.'" Then, the priests and the people standing in the courtyard, when they heard the explicit Name from the mouth of the High Priest, would bend their knees, bow down and fall on their faces, and they would say, "Blessed be the Honored Name of God's Sovereignty forever."

One must detail the sin, as it is states: Please, this people have sinned a great sin, and have made themselves a god of gold, these are the words of Rabbi Yehuda ben Bava. Rabbi Akiva says (Psalms 32:1): Fortunate is he whose transgression is forgiven, whose sin is hidden.

It is not necessary to detail the sin. But if you want to detail the sin, you may do so. If one is confessing quietly, it is proper to detail the sin. [But if you are praying loudly, or when the Chazzan is going over the prayer, the sin should not be elucidated. That which we say “on the sin....” (אל חטא) outlined one after the other is not considered detailing (the sin) even though everyone says the same thing; it is nothing more than the customary arrangement (נוסח) of the prayer.]