After 20 years I'm receiving a lump sum social security from a Western European county

My question is where do I declare this income (which form)? Is this a "miscellaneous" income or something else since I earned this while working in Europe? It seems like it would be exempt from taxation since this was derived from the monies my European employers paid into the State (https://www.irs.gov/individuals/international-taxpayers/foreign-earned-income-exclusion).