Mich. Comp. Laws § 449.15: Partners; joint and severable liability.

Sec. 15.

(Nature of partner's liability). Except as otherwise provided by section 46, all partners are liable for both of the following:

Jointly and severally for everything chargeable to the partnership under sections 13 and 14.

Jointly for all other debts and obligations of the partnership. However, a partner may enter into a separate obligation to perform a partnership contract.