They spent $6.5 billion on "Technology and content" in 2013. $100 million is ~1.5% of that. So not quite a rounding error, but close. They also spent ~$5 billion in 2012 and I guess they will spend a similar amount this year.

(That segment includes all sorts of spending, but in the 2013 annual report they do call out devices as one of the focuses of that spending)