Wander around on the IRA Info Wks.  I don't remember where but somewhere there should be a checkbox for Roth IRA open for at least 5 years.  You can also enter the basis (but that shouldn't matter in this case).  If you're confident there's no tax / penalty on this, I would just put $0 in box 2a.  IMO if an IRA 1099-R doesn't check the "Taxable amount not determined" box, they're doing it wrong.  The IRS views all traditional IRAs as one big IRA and all Roth IRAs as one big Roth IRA.  So there's no way one institution can know with any certainty whether or not other accounts are open.