Hilton Hotels Corp. co-chairman Barron Hilton will give 97 percent of his estimated $2.3 billion fortune when he dies to the foundation established by his father.

Hilton, 80, will make an immediate donation of $1.2 billion to the Los Angeles-based Conrad H. Hilton Foundation, representing his share of the proceeds of the sale of the second-largest U.S. hotel chain and the pending sale of Harrah's Entertainment Inc., foundation Chief Executive Officer Steven Hilton said in a statement. The contribution boosts the foundation's value to $4.5 billion.

"Working to alleviate human suffering around the globe, regardless of race, religion or geography, is the mandate of the foundation set by my grandfather, Conrad Hilton, and now reinforced by my father, Barron Hilton," Steven Hilton said.

Blackstone Group LP paid $20 billion for Hilton in the largest-ever transaction for a hotel company earlier this year. Apollo Management LP and TPG Inc. agreed to pay $17.1 billion for Harrah's Entertainmentin the largest casino buyout ever, which is expected to close next year.

Conrad Hilton, who bought his first hotel in 1919, created the foundation in 1944 and left almost all of his fortune to it when he died in 1979. Since its inception, more than $560 million has been distributed.

More than 50 percent of the money funds international initiatives such as sanitation and water systems in developing countries; supportive housing for mentally ill homeless people and homeless mothers and children in the United States; blindness prevention; drug-abuse prevention among young people; and education for children with disabilities.