I believe it takes only a few days. You may be thinking of Starwood Preferred Guest transfers to ANA which are reported to take much longer.
Ii will be transferring both MR points and SPG points from 4 different accounts. I want to coordinate the initiation of the transfers so all points hit at about the same time. All points have to be in ANA before I make the call to get the 2 biz class tickets I need for a complicated multi stopover itinerary involving tpac and domestic China segments.