The pledge comes as a similar inquiry in the House remains mired in acrimony.
The Senate hearing begins on Thursday. Jared Kushner, President Donald Trump's son-in-law, is set to appear next week.
Ahead of the opening, Ranking Democrat Mark Warner said there may have been "1,000 internet trolls in Russia generating fake news stories".
He said Thursday's session would examine how Russia may have used technology to spread disinformation in the US, including the possible generation of fake news for voters in key states, such as Wisconsin, Michigan and Pennsylvania.
"We are in a whole new realm around cyber that provides opportunity for huge, huge threats to our basic democracy," Mr Warner said. "You are seeing it right now."
Former National Security Agency director Keith Alexander will be one of those testifying on Thursday.
Senate Intelligence Committee chairman Richard Burr said the panel would not shy away from the truth.
"This investigation's scope will go wherever the intelligence leads," he said.
When asked if he had seen any links between Mr Trump and Russian interference, he said: "We know that our challenge is to answer that question for the American people.".
The Trump presidency has been unable to shake off allegations that members of its team colluded with Russian officials during the election campaign. The president has regularly dismissed the claims as "fake news" and Russia has also ridiculed the allegations.
Devin Nunes has been under fire for his handling of the House inquiry
Mr Burr was a security adviser to the Trump campaign but insists he remains objective.
The House Intelligence Committee into the matter has been beset by partisan disputes.
Ranking Democrat Adam Schiff has insisted panel chairman Devin Nunes remove himself, after accusing him of colluding with the White House.
Last week, Mr Nunes went straight to the White House after hearing allegations about surveillance of Mr Trump's team, rather than sharing them with Democrat colleagues on the panel.
He later apologised but insists he remains an objective chairman and will not step down.
As well as the two houses of Congress, the FBI is also conducting an investigation into the matter.