Br. Syed the following verse clearly links both Millat and Deen to identify with one another.
[22:78]: And strive for Allah with the striving due to Him. He has chosen you and has not placed upon you in the DEEN any difficulty. [It is] the MILLAT of your father, Abraham. Allah named you “Muslims” before [in former scriptures] and in this [revelation] that the Messenger may be a witness over you and you may be witnesses over the people. So establish prayer and give zakah and hold fast to Allah. He is your protector; and excellent is the protector, and excellent is the helper.
Further, the term Millat in Arabic is translated as follows by two lexicons:
Lane, p. 382, supplement: Millat- a religion, a way of belief and practice in respect of religion.
Allama Parwez, p. 1559: In Quran the word Millat is used to describe method of deen. Islam is called Millat-e-Ibrahim meanings that method/way Ibrahim adopted in line with revelations from God.
It is therefore obvious the Creed of Ibrahim is comprising of methods/ways/rites to practice Deen.