The one billion unit number is largely symbolic, but does make for a convenient milestone. More important is smartphones out shipment of feature phones, which means that by the end of this year the number of active smartphone is likely to outstrip the number of active feature phones (there's some debate as to exactly when this will happen, given that feature phones typically have a long life cycle than smartphones).
The top 5 smartphone vendors for 2013 were Samsung (313.9 million units), Apple (153.4 million), Huawei (48.8 million), LG (47.7 million), and Lenovo (45.5 million).
By way of comparison Nokia's total Lumia smartphone shipments were 30.2 million. Only by including the "smartphone like" Asha Full Touch devices would Nokia be rated as a top 5 smartphone manufacturer (~50 million). Asha Full Touch devices are generally not considered smartphones by most market researc companies, though they do occupy a similar pricing and customer segment to low end smartphones.
Windows Phone's devices as a while made up less than 35 million of total smartphone shipments, giving a market share for 2013 for Microsoft's mobile platform of under 3.5%.
For mobile phones as a whole (i.e. smartphones and feature phones) IDC reports total shipment volumes of 1,821 million units. The top 5 manufacturers are Samsung (446 million), Nokia (251 million), Apple (153.4 million), LG (70 million), Huawei (55.5 million), with other manufacturers making up the remaining 845.2 million.
Nokia is in the overall top 5 due it's dominance in the feature phone space, where it is the leading manufacturer (218 million), ahead of Samung (133 million) in second place. Apple was in third place, LG and fourth, with Huawei in fifth.
Q4 2013 numbers
Q4 2013 also saw record numbers, with total shipments of 284.4 million, up 24.2% from same period in 2012. However, it is notable that year-on-year growth was strongest amongst the newer entrants to the top 5: Huawei (56.5%), Lenovo (47.3%), and LG (53.2%), although in part this reflects their smaller starting base.
Windows Phone's share of these shipments was between 9 and 10 million (estimate), representing a market share of between 3.1% and 3.5%.