The news comes a week after Uber was reported to be on the verge of closing the round.
The announcement, revealed in a blog post by company founder Travis Kalanick, means that Uber could be valued at up to $40 billion (£25 billion), outstripping the likes of Twitter which has a market cap of $25 billion.
Uber has proved controversial in many of the cities it operates in, with licensed taxi drivers claiming the firm is breaking the law because its cabs don't have a regulated meter. The app has also received temporary bans in Germany.
Last month, Uber confirmed it was going to investigate one of its New York executives for allegedly tracking a journalist's movements without her knowing.
In a separate incident last week, another Uber executive said the company should create an army of private investigators to track the private lives of journalists who reported on the company.
The blog post on the funding can be found in full below.
2014 has been a year of tremendous growth for Uber. It was just a year ago that Uber was operating in 60 cities and 21 countries - today we are in over 250 cities in 50 countries. We are 6 times bigger today than 12 months ago - and grew faster this year than last. This progress is remarkable, but it is in the coming years that Uber truly scales and the impact in cities becomes visible.
In 2015 alone, Uber will generate over 1m jobs in cities around the world and with that millions of people may decide that they no longer need to own a car because using Uber will be cheaper than owning one. Parking could become less strained in our biggest cities, and city congestion may actually start to ease due to uberPOOL's expansion and success.
This kind of continued growth requires investment. To that end, we have just raised a financing round of $1.2 billion, with additional capacity remaining for strategic investments. This financing will allow Uber to make substantial investments, particularly in the Asia Pacific region.
This kind of growth has also come with significant growing pains. The events of the recent weeks have shown us that we also need to invest in internal growth and change. Acknowledging mistakes and learning from them are the first steps. We are collaborating across the company and seeking counsel from those who have gone through similar challenges to allow us to refine and change where needed.
Fortunately, taking swift action is where Uber shines, and we will be making changes in the months ahead. Done right, it will lead to a smarter and more humble company that sets new standards in data privacy, gives back more to the cities we serve and defines and refines our company culture effectively.
We have an interesting journey ahead and I'd like to thank all of the riders, drivers and Uber employees who have made it possible to get this far. I'm inspired and energized every day by the work we do, the people in our community we serve and the impact we can have in bringing positive change to cities around the world.