"I mutilated a dead body," Stephen Grant told Judge Diane Druzinski.
The mutilation charge carries a maximum penalty of 10 years in prison.
Stephen Grant insisted he had nothing to do with his wife's disappearance after he reported her missing Feb. 14.
He fled March 2 as police searched the couple's home but was captured two days later in a remote, snowbound state park in the far northern Lower Peninsula. Police said he made a graphic confession while being treated for hypothermia at a hospital.
Authorities say Grant killed his 34-year-old wife at their Washington Township home, about 25 miles north of Detroit. Body parts were found in their garage and a nearby park.
