FILE - In this June 23, 2008, file photo, members of the Tisch family, from left, Wilma, Andrew, Joan, James, and Jonathan Tisch, attend the opening bell ceremony at the New York Stock Exchange in New York. Joan Tisch, a noted philanthropist and the widow of former New York Giants co-owner Bob Tisch, has died at 90. The NFL football team said she died Thursday, Nov. 2, 2017, after a brief illness but did not give a cause. (AP Photo/Mark Lennihan, File)
FILE - In this June 23, 2008, file photo, members of the Tisch family, from left, Wilma, Andrew, Joan, James, and Jonathan Tisch, attend the opening bell ceremony at the New York Stock Exchange in New York. Joan Tisch, a noted philanthropist and the widow of former New York Giants co-owner Bob Tisch, has died at 90. The NFL football team said she died Thursday, Nov. 2, 2017, after a brief illness but did not give a cause. (AP Photo/Mark Lennihan, File)

New York — Joan Tisch, a billionaire matriarch of the family that co-founded Loews Corp. and co-owns the New York Giants football team, has died. She was 90.

She died Thursday after a brief illness, according to the Giants website. No cause was given.

With a net worth of $4.5 billion, according to the Bloomberg Billionaires Index, Tisch was one of America’s richest women.

The 2005 death of her husband, Robert, and the 2003 death of his brother and business partner, Laurence, left her and her sister-in-law, Wilma “Billie” Tisch, overseeing a multibillion-dollar fortune.

Their husbands turned Loews, a theater chain when they bought it in 1959, into a holding company with hotels, energy companies and insurer CNA Financial Corp. Its principal units today include CNA, Diamond Offshore Drilling Inc., Boardwalk Pipeline Partners LP and Loews Hotels & Resorts. Loews spun off Lorillard Inc., maker of Newport cigarettes, in 2008, after owning it for more than 30 years.

Her husband owned half of the Giants football team from 1991 until his death.

That share is now owned by their three children — Steven Tisch, a film producer and chairman of the team; Jonathan Tisch, who runs Loews with two cousins, James and Andrew Tisch; and Laurie Tisch, who has helped guide New York City cultural institutions including the Center for Arts Education, the Children’s Museum of Manhattan and the Laurie M. Tisch Illumination Fund.

The Tisch family’s large philanthropic footprint in Manhattan includes Tisch Hospital at NYU’s Langone Medical Center, which includes the Joan H. Tisch Center for Women’s Health; Tisch School of the Arts at New York University; and the Tisch Family Zoo in Central Park.

Following her husband’s death from a rare form of brain cancer, Joan Tisch donated $10 million to Duke University Medical Center to create the Preston Robert Tisch Brain Tumor Center.

She was a longtime board member at 92nd Street Y in Manhattan, which presents musical and literary events through its Tisch Center for the Arts.

Another of her longstanding charitable priorities was helping those with AIDS and the HIV virus. She served on the board of New York-based Gay Men’s Health Crisis and, with her husband, gave $3.5 million to provide the group with office space in Manhattan.

Joan Hyman was born July 14, 1927, the daughter of N. Howard Hyman and his wife, Mae, according to U.S. Census records.

Her father was a Manhattan dentist who helped disabled war veterans attend theater and sporting events. He persuaded Jack Mara, then president of the Giants, to donate 400 seats for each home game to disabled fans and their companions, according to a news release from Loews upon his death in 1981.

Tisch received a bachelor’s degree in English in 1948 from the University of Michigan, in Ann Arbor, where she met her husband.