It was announced as $1b prelaunch, correct? It can only have gone sharply up from there, especially if you consider moves like Titanfall exclusivity to fall under it. (Though I suppose that could also be booked in the form of future incentives rather than immediate payments.)
The only $1b figure from Microsoft I recall was the investment in games, which may have been used for Titanfall and Gears, or maybe not. The $1b in games was announced before those deals supposedly took place.
The only article I can find about the Xbox One launch marketing campaign spend says it was $100 million dollars.
Happy to be wrong, just want to make sure we're discussing facts.