1099R taxation of life insurance death payout

I received a 1099-R for a life insurance payout as beneficiary for my wife's death.  It has code 0 (zero) in box 7 and claims to be taxable.  It was issued by her former employer.  The IRA/Sep/Simple box is checked.  It is not an IRA.  The amount was promised upon her death.  Why is this taxable and what does code 0 mean?  This code is not an option in TurboTax dropdown menu.