SAN DIEGO (AP) — Joan Kroc, the billionaire philanthropist who became owner of the San Diego Padres after her husband’s death in 1984, died of brain cancer Sunday at age 75.

Kroc took over the Padres when McDonald’s Corp. founder Ray Kroc died at 81. She remained a high-profile owner until selling the team in 1990.

Her first passion was philanthropy, and it is estimated Kroc, whose net worth was placed at $1.7 billion, gave away hundreds of millions.

“She was a woman of generous spirit and a loving heart,” said former San Diego Mayor Maureen O’Connor.

She gave to causes promoting world peace, education, health care, cancer research, the arts and the fight against AIDS, and provided help for the Midwest when it was devastated by floods in the 1990s.

When 21 people were killed in 1984 in a shooting rampage at a McDonald’s in San Ysidro, Kroc started a relief fund for victims’ families the next day, donating $100,000. McDonald’s added $1 million.

Kroc’s donations created Notre Dame’s Joan B. Kroc Institute for International Peace Studies in 1986 and the University of San Diego’s Joan B. Kroc Institute for Peace and Justice in 2001. She was also a major benefactor of the Carter Center in Atlanta.

Kroc contributed more than $90 million to the Salvation Army for a 121/2-acre arts and recreation center in San Diego, said Maj. Cindy Foley, the center’s administrator.

“She embodied the word generosity,” Foley said.

Born Aug. 27, 1928, in St. Paul, Minn., Kroc was a musician and music teacher for many years. She married Ray Kroc, who founded McDonald’s in 1955, in 1969. It was her second marriage and his third.

Kroc is survived by a daughter, four granddaughters and four great-grandchildren.