Russia Sanctions Explained: A Look at the Measures Donald Trump Could Roll Back

— -- President-elect Donald Trump floated the idea over the weekend of a new negotiation with Russia that would involve rolling back President Obama's crippling economic sanctions against Russia in exchange for its enhanced reduction of nuclear arms.

"They have sanctions on Russia -- let’s see if we can make some good deals with Russia," Trump told The Times of London.

"For one thing, I think nuclear weapons should be way down and reduced very substantially, that’s part of it. But Russia’s hurting very badly right now because of sanctions, but I think something can happen that a lot of people are gonna benefit."

Trump's pick for secretary of state, former oil executive Rex Tillerson, called sanctions against Russia a "powerful tool," but he spent more time defending against accusations that he lobbied against the sanctions while leading ExxonMobil, rather than articulating their effectiveness.

So, what exactly are the sanctions that Trump could erase in a deal with Russia?

President Obama's sanctions by executive order began with Russia's illegal military invasion and annexation of Crimea. Its subsequent military aggression in eastern Ukraine led to even more sanctions.

On March 6, 17 and 20 and then on Dec. 19 of 2014, President Obama issued sanctions via four separate executive orders targeting Russian individuals and entities in direct response to the military actions in Ukraine.

"We have designated a number of Russian and Ukrainian entities, including 14 defense companies and individuals in Putin’s inner circle, as well as imposed targeted sanctions limiting certain financing to six of Russia’s largest banks and four energy companies," the U.S. State Department said of these sanctions.

"We have also suspended credit finance that encourages exports to Russia and financing for economic development projects in Russia, and are now prohibiting the provision, exportation, or re-exportation of goods, services (not including financial services), or technology in support of exploration or production for deepwater, Arctic offshore, or shale projects that have the potential to produce oil in the Russian Federation, or in maritime area claimed by the Russian Federation and extending from its territory, and that involve five major Russian energy companies," the State Department added.

In other words, the sanctions have blocked major U.S. financial institutions from doing business with Russia and prevents U.S. oil companies from making new deals with Russia.

These moves have brought significant pain to Russia, exacerbating a severe recession prompted by low oil prices that has seen the average Russian's income lose almost half its value. Blocked from U.S. and European financial markets, Russia’s state-run financial firms have struggled to refinance themselves, leaving some vulnerable to defaulting on their debts.

The sanctions have also been accompanied by a de facto freeze on foreign investment in Russia, with investors spooked by the measures and fears of further Kremlin adventures. Even companies not targeted by the sanctions have effectively paused many investments, unwilling to take the risk.

Likewise, the U.S. sanctions have played a key role in buttressing the European Union’s own sanctions regime, which inflict more direct punishment on Russia.

On his final overseas trip as vice president, Joe Biden met today with Ukrainian President Petro Poroshenko and called on the incoming Trump administration to leave the sanctions in place until "Russia returns full control to the people of Ukraine."

In addition to the Ukraine-related sanctions, President Obama issued additional sanctions on Dec. 29 that Trump could undo -- retaliatory measures for Russia's cyber-intrusions into the 2016 U.S. presidential election.

Those sanctions ordered 35 Russian intelligence operatives out of the country, shut down two Russian compounds, in Maryland and New York, used by Russian personnel for intelligence-related purposes, and sanctioned five Russian entities and four individuals.

ABC News' Patrick Reevell in Moscow contributed to this report.