@Bernhard --
Under Pennsylvania law, payments commonly recognized as old age or retirement benefits are not subject to tax. In order to be considered exempt retirement benefits, the payments must come from an eligible Pennsylvania retirement plan and must be paid to persons retired from service after reaching a specific age or after a stated period of employment.
Scroll down to "Criteria for A Plan to Qualify as an Eligible Pennsylvania Retirement Plan" in this reference for more details:
https://www.revenue.pa.gov/FormsandPublications/PAPersonalIncomeTaxGuide/Pages/Gross-Compensation.as...
I suggest you contact a local tax professional if you're unsure whether or not your foreign pension income qualifies under these rules.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
