During 2006's season five, the show's highest-rated season, American Idol averaged nearly 31 million viewers tuning in to watch live or that same day, according to Nielsen ratings. Since then, viewership and audience engagement online have steadily declined, and advertisers such as Coca-Cola (KO), Ford (F)and AT&T (T) -- which once paid tens of millions of dollars to secure slots during the show -- are backing out of their sponsorships.
When American Idol debuted back in June 2002, the singing competition was an instant hit and began to drive profits for Fox. It was based on a British show called Pop Idol, after television executive Elisabeth Murdoch, daughter of 21st Century Fox Chairman Rupert Murdoch, did some convincing at the network.
American Idol quickly made original judges Simon Cowell, Paula Abdul and Randy Jackson, along with host Ryan Seacrest, celebrity icons. Contestants including Kelly Clarkson, Chris Daughtry and Carrie Underwood went on to have remarkably successful careers.
But Fox has lost a lot of love lately, especially among viewers in the coveted 18-49 age demographic. This season, Fox viewership among that demographic is at its lowest level yet, putting Fox in fourth place in both total viewers and among that audience segment. Fox is scheduled to launch nine new shows in the 2015-2016 television season, hoping to refresh its lineup and garner more support from millennial viewers.
According to Fox, the final season of American Idol will begin in January 2016 and will be a "season-long celebratory event." Seacrest will be back, along with judges Jennifer Lopez, Keith Urban and Harry Connick Jr.
Here's a look back at the Idols crowned during the show's past 14 seasons.
Season 1: Kelly Clarkson
One of the most successful Idol stars to-date, Kelly Clarkson's songs continue to chart on the Billboard Hot 100 today. She is often referred to as the "Original American Idol" after winning in the show's premiere season.
Season 2: Ruben Studdard
Ruben Studdard is best known for his R&B and gospel renditions of songs. He beat runner-up Clay Aiken by a small margin.
Season 3: Fantasia Barrino
Female R&B vocalist Fantasia Barrino won in 2004, after what was viewed by many fans as a controversial elimination of Jennifer Hudson.
Season Four: Carrie Underwood
Carrie Underwood has won more Grammy Awards to date than any other Idol contestant, and has sold more than 14 million albums in the U.S. alone. She is a country superstar today thanks to her beginning on Fox's show in 2005.
Season 5: Taylor Hicks
In 2006, Taylor Hicks outperformed Katharine McPhee, Kellie Pickler and Chris Daughtry -- all of whom went on to successful music careers. Notably, this was the highest-rated season of Idol thus far.
Season 6: Jordin Sparks
In 2007, Jordin Sparks beat runner-up Blake Lewis. Notably, Spark's season included the first "Idol Gives Back" telethon-inspired event, which raised more than $76 million in corporate and viewer donations combined.
Season 7: David Cook
David Cook outperformed David Archuleta in 2008, becoming the first "rocker" to win the show. "Idol Gives Back" returned during Cook's season and raised $64 million for charity.
Season 8: Kris Allen
Kris Allen battled with Adam Lambert in the finale to become his season's winner. "Idol Gives Back" was canceled due to a global recession., and the panel of judges got its first change when a fourth judge, Kara DioGuardi, joined the team.
Season 9: Lee DeWyze
This was Simon Cowell's final season, and Ellen DeGeneres joined as a judge to replace Paula Abdul. According to Entertainment Weekly, this was the first season when neither finalist achieved significant album sales.
Season 10: Scotty McCreery
Jennifer Lopez and Steven Tyler joined the panel alongside Randy Jackson, while DeGeneres, Cowell and DioGuardi departed. When McCreery won, he became the youngest male winner and the fourth male in a row to win Idol.
Season 11: Phillip Phillips
Phillip Phillips became "Idol's" youngest winner, and his coronation song, "Home," has achieved great success with sales of more than 4 million copies in the U.S.
Season 12: Candice Glover
Judges Lopez and Tyler left the show, and were replaced with Mariah Carey, Keith Urban and Nikki Minaj, though Jackson still remained. In 2013, Glover became the first woman to win "Idol" since Jordin Sparks back in 2007.
Season 13: Caleb Johnson
Judges Randy Jackson and Keith Urban worked alongside Jennifer Lopez and Harry Connick Jr. to mentor contestants. Carey and Minaj left the judges panel after one season. When Caleb Johnson was announced winner of his season, Jena Irene was crowned runner-up.
Season 14: Still to Come
The two-part Idol season finale airs at 9 p.m. ET Tuesday and 8 p.m. ET Wednesday.