Bank of America CEO Brian Moynihan said that the adoption of technology at the second-biggest U.S. lender has allowed him to cut 100,000 workers in less than a decade.

"The straightforward way to get people to feel it is this: We had 288,000 people when I took over as CEO on Jan 1st [2010]," Moynihan said in a Tuesday interview with Becky Quick at CNBC's Net/Net Summit at the New York Stock Exchange.

"We had 204,000 last quarter. Step back and think about that," Moynihan said. The reduction is "more employees than Delta has I think. All caused by the ability to apply technology to processes and capabilities, and customer behavior changed."

Moynihan appears to be correct: Delta Air Lines has more than 80,000 employees, according to its website.

Bank of America's headcount peaked at about 305,000 after he took over, Moynihan said. The bank hired furiously in the aftermath of the financial crisis to help resolve mortgage-related woes tied to the acquisition of Countrywide Financial.

Bank of America began plotting out its digital strategy in 2008 due to a need to reduce costs, Moynihan said. While online banking has been around since the 1990s, Apple's introduction of the first iPhone in 2007 was a game changer, he said. It effectively allowed customers to carry a bank branch in their pockets.