What on earth did they spend the money on
It's a marketing statistic, it'll be 90% bullshit. It's in the marketing department's best interests to inflate the total production cost as high as possible because it makes the game sound like it's a can't-miss epic (see: GTA4 and Avatar both being hyped as "the most expensive movie/game ever!" at launch as well).
Firstly, about 50% of that figure will be marketing budget, and the other haft development. AAA games have stupidly high marketing budgets now, mostly because marketing departments are good at convincing the rest of the company that it's worth the money.
Of that marketing money, not all of it will be "real". Something like giving an exclusive review to one magazine is nearly free for Blizzard, but marketing will deem it to be "$100k effective marketing spend", ie. they think they got the equivilent of 100k of marketing from it.
Of the development money, most of it will be counted twice. For example they'll have counted the salaries for the entire QA, HR, legal, etc. departments, despite the fact that they are supporting the whole studio's games output.
Similarly they'll have fudged the actual development team's numbers - so if the team at completion is 50 they'll have calculated 50 * numYears salaries, even if there was only two people on the project for the first year.
They'll be a whole load of these fudged estimates added together, with each on rounded up to a nice fat number at each step, so the final figure is completely removed from reality.
I'm sure SC2 wasn't cheap to produce, but this figure is just marketing BS. Nothing to see here people, move along.