So what did he mean when he said that Iran would be able to access its holdings abroad?
"A senior American official said Saturday that Iran will be able to access about $50 billion of a reported $100 billion in holdings abroad, although others have used higher estimates."
Prior to the sanctions, Iran had billions of dollars invested in foreign banks and infrastructure. Their access to this money was cut off when the sanctions were put into place and we're slowly allowing them access. Here's an article from 2014 with more detail:
Access money that is outside of Iran. Most countries have assets in other countries. Preventing the movement of this money is pretty typical form of sanctions.
"A senior American official said Saturday that Iran will be able to access about $50 billion of a reported $100 billion in holdings abroad, although others have used higher estimates."