Google may not be able to keep all the tax losses. It was originally reported that google would save $700M a year through 2019.* I'm not sure that they those losses are severable from the rest of the company.
There are two types of tax losses. There are those related to previous losses that Google captured on acquisition. The $700MM a year estimate relates to the anticipated future losses of Motorola. While Google is losing that benefit, it is by definition less than the amount lost! So it's not actually a benefit.
* E.g. http://www.reuters.com/article/2011/08/31/us-motorolamobilit...