Underlining his determination to crack down on costs, Citigroup Inc. Chief Executive Michael Corbat set out plans Wednesday to cut 11,000 jobs, close 84 branches and retreat from consumer banking in a handful of countries.

Plans for workforce reductions were under way when Mr. Corbat was named to succeed Vikram Pandit as CEO in October, according to people familiar with the bank. But Mr. Corbat turned up the heat, demanding last month that some business heads increase their cost-reduction targets by a third, according to...