MelindaS1: Unless the Form 1099-R was prepared improperly or the rollover was mishandled, a Form 1099-R that reports a distribution only part of which was rolled over cannot have code G in box 7 because code G means that the entire gross amount was rolled over. That combined with the details provided from the 1099-R Summary indicate that the distribution is therefore from a traditional account in an employer plan and that the rollover was an indirect rollover, so the Form 1099-R must have code 1, 2 or 7 in box 7.
frenzel: The distribution consisted of $50,000 of pre-tax funds and $150,000 of after-tax funds. (Presumably at least $5,000 of this distribution went to mandatory tax withholding.) By operation of law, a rollover of $150,000 of that distribution consists of all $50,000 of the pre-tax funds and $100,000 of the after-tax funds, leaving $50,000 of after-tax funds not rolled over. That's what the 1099-R Summary is telling you. Because the entire $50,000 of the pre-tax funds was rolled over, the taxable amount of the distribution is $0.
Perhaps you desired that the portion rolled over consisted of the entire $150,000 of after-tax funds, leaving the $50,000 of pre-tax funds not rolled over and therefore taxable, but the tax code does not allow you to designate which portions are the ones rolled over. As I mentioned, the tax code dictates that the first portion of the rollover comes from the otherwise taxable portion of the distribution, so in this case that portion becomes nontaxable due to having been rolled over.
