The Withholding Summary report lists all sources for Federal, State, and Local Withholding by form (W-2, 1099-MISC etc.). At the bottom of the report, there is an All Other Withholdings field that applies to only federal withholding.
Sources for withholding that are reported in the All Other Withholding field are:
To access the withholding summary report:
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the webpage or document at the time it is accessed.