Forbes recently ranked the highest-paid 'American Idol' alumni, and Carrie Underwood was by far the biggest-earning singer over the past 12 months, raking in around $20 million. The country beauty outranked Adam Lambert and Chris Daughtry, who tied for second on the website's rankings of the former 'Idol' contestants' estimated recent earnings.

Underwood, the Season 4 winner, raked in as much money as the next four Idols on the list combined. The website says she made a large chunk of her money from her busy touring schedule, which included 80 concert dates. Underwood also ranked highly on a recent Forbes list of the Richest Celebrities Under 30.

Only five of the top ten earners actually won their season of 'Idol.' Non-winners Lambert and Daughtry tied for second place with $6 million each. The site treated Daughtry's self-named rock band as a single entity, so Daughtry's personal share of the wealth was probably a little less than that.

Next in the rankings are three 'Idol' victors: Fantasia Barrino ($4 million), Jordin Sparks ($3 million), and Kelly Clarkson ($2.5 million). As one of the most successful pop artists to come from 'Idol,' Clarkson is lower on the list than you might expect, but that's mainly because she wasn't touring regularly. In the prior year, Forbes estimates that she made $11.7 million.

Rounding out the list of 2011 'Idol' millionaires are Jennifer Hudson ($2 million), Kellie Pickler ($1.8 million), Clay Aiken ($1.5 million), and the trio of Katharine McPhee, David Archuleta, David Cook, who earned estimated hauls of $1 million each. Notably missing from the list are past winners Kris Allen and Ruben Studdard, as well as the Season 10 Idols, many of whom are good bets to appear on next year's list after they have a chance to tour and release new albums.

Watch Carrie Underwood Perform with Lauren Alaina on the 2011 'American Idol' Finale