The trade was first reported by Fox Sports.
Even better, it reunites him with one of his top targets in Denver.
Marshall made the Pro Bowl for the third time last year, when he had 81 catches for 1,214 yards and six scores. But he also dropped at least four potential touchdown catches and failed to end his career-long playoff drought.
Last July, Marshall disclosed he was diagnosed earlier in the year with borderline personality disorder, which stems from such things as a negative self-image and a fear of failure. Then at midseason he said efforts to keep his emotions on an even keel have hurt his play, and before a Monday night game he claimed he goal was to get ejected before halftime.
"Hate to see my boy B Marshall go," running back Reggie Bush tweeted. "That's the league for you, one day your hear next day your gone. Chicago is getting one hell of a player!"
In Chicago, it led to a big sigh of relief.
For years, they've lacked a go-to receiver, and now, they have one.
They tried to make their record-setting return specialist Hester their top threat. They brought in Roy Williams last year, hoping he could rediscover some of the form that made him a Pro Bowler in Mike Martz's system in Detroit after a disappointing run in Dallas, but that didn't happen.
Throw in the uncertainty surrounding Johnny Knox after his season-ending back injury and the need was glaring - not that it was the only hole.
The lack of depth was a big reason why they fell apart after a 7-3 start, dropping five straight before winning the final game and missing the playoffs after making the NFC title game the previous year.
The freefall started after Cutler broke his right thumb late in a win over San Diego on Nov. 20 and got another push when Matt Forte sprained a ligament in his right knee against Kansas City on Dec. 4, leaving the offense without its two best players.
The collapse led to Angelo's dismissal and the Bears parting with Martz as their offensive coordinator.
They promoted offensive line coach Mike Tice to replace him and hired Jeremy Bates as quarterbacks coach, reuniting him with Cutler.
Now, Marshall's in the mix, too.
"Jay Cutler and Jeremy Bates makes it great," Marshall's agent, Kennard McGuire wrote in a text message.
When Marshall played against the Bears in 2010, he drew a penalty for taunting by flipping the ball at Cutler, standing in front of the bench.
"We're good friends," Marshall said at the time. "I was just messing with him."
Marshall wore out his welcome in Denver, partly because of a long legal record. He was involved in a New Year's Eve fight that led to the 2007 drive-by slaying of Broncos teammate Darrent Williams.
Last year Marshall's wife was arrested after he was stabbed in the abdomen with a kitchen knife during a domestic dispute. Charges were later dropped.
AP Sports Writer Steven Wine in Miami contributed to this report.