Wonder just how much it costs to phase out iDEN and WiMAX networks and put all your eggs in one, CDMA / LTE-flavored basket? Well, Joe Euteneuer, Sprint's CFO, just offered up a frank answer here at its "Strategy Update" event: $10 billion over the next two years. That's a heckuva lot more than the $4 billion to $5 billion Wall Street was expecting, but Euteneuer assured all the suited-up financial analysts in the room that the company should save $10 billion to $11 billion through 2017 (a figure widely reported before today), with $4 billion of that resulting from not having to maintain the 'ol ball and chain iDEN network anymore. Now it's true, we're a minority in this meeting of industry analysts, but you don't need to be a banker to understand that's one telling figure: clearly, the company's betting its future not just on the (CDMA!) iPhone, but LTE's brand of 4G.