The game's developer says the downloadable content will arrive on January 24 on Xbox Live for players with paid subscriptions to Call of Duty Elite.
The mega hit reached the milestone a day faster than "Avatar" did.
The new Call of Duty game easily beats the previous five-day record holder: last year's Call of Duty: Black Ops, which pulled in $650 million.
Call of Duty: Modern Warfare 3 has shifted over 6.5 million copies and generated $400 million of revenue in its first 24 hours.
Launching next week, the game should best its predecessor, Call of Duty: Black Ops, to take the crown of the bestselling game of all time, an analyst says.
Activision says the game generated more than $400 million and sold 6.5 million units in its first 24 hours on store shelves, easily beating its predecessors.
Battlefield 3 and Modern Warfare 3 go head-to-head in CNET's battle of the first-person military shooters. Which one is the better game?
The highly anticipated first-person shooter, which has the potential to break entertainment-industry sales records, is available now on all major consoles and the PC.
The electronics big-box retailer is pushing its mobile arm hard this holiday season with a hefty bump in its marketing budget, allowing for more promotions.
For those who fear being bruised and battered by the hardcore online scene, Infinity Ward's Robert Bowling offers some advice on how the new game will help you get your skills up to scratch.