Samsung paid Microsoft $1 billion last year to build Android phones

The filing also shows that MicrosoftMicrosoft offered to reduce Samsung's payments if it developed Windows tablets and phones alongside its AndroidAndroid products. Alles zu Android auf CIO.de Alles zu Microsoft auf CIO.de

The information came to light in a lawsuit that Microsoft filed against Samsung in August. The original complaint was partly blacked out to hide confidential business information, but the revised filing made Friday is unredacted.

The two companies signed an agreement in late 2011 in which Samsung agreed to pay royalties to Microsoft for seven years for the use of its patented technologies.

Microsoft has maintained for years that Android infringes its patents, and many other companies besides Samsung have signed such agreements.

The contracts are typically highly confidential, so it's unusual to get a look at the numbers behind them.