Aviva, which employs 2,000 people at its life and general insurance business in York and 1,500 at its life and health insurance operation in Sheffield, said it hopes to keep redundancies to a minimum as it slashes costs, with some of the redundancies coming from natural staff turnover. Aviva employs around 30,000 staff in total.
It has not given a split of which teams or offices will be affected, but said the cuts will be made across its UK and international operations.
The group said savings will also be made across central costs, contractor and consultant spend, reduction in project spend and in other areas.
Aviva also announced plans to split its UK life and general insurance businesses to enable stronger accountability and greater management focus.
The moves are part of a revamp of the group by new chief executive Maurice Tulloch, who took on the top job in March.
He said: "Reducing Aviva's costs is essential to remain competitive and this means tough decisions and job losses which I do not take lightly.
"We will do all we can to minimise redundancies and support our people through this.
He added: "I am also determined to crack Aviva's complexity, an issue which has held back our performance for too long."
Aviva has major UK offices in York, Sheffield, Norwich, Bristol, Perth and Glasgow.
The group said its separated UK life business will be headed up by Angela Darlington, formerly chief risk officer, while previous Canadian boss Colm Holmes has been appointed chief executive of UK general insurance.
Customers will not see any changes as a result of the UK split, it said.
The combined business was previously led by Andy Briggs, who stepped down in April just weeks after he missed out on the top job.
He remains with the insurer until October to support an orderly transition.
Mr Tulloch, who took over from former CEO Mark Wilson, said in April he was leading a review of the UK businesses "to ensure the appropriate management structure".