There are several accepted abbreviations for the word billion. It is most commonly abbreviated as "B," as in $3B to indicate $3 billion. Other abbreviations include "bill." and "bn," as in $3bill. or $3bn to indicate $3 billion.
The term "billion" is has different meanings in different parts of the world. In the United States, 1 billion is represented by 1 followed by nine zeros. In the U.K., a billion is 1 followed by 12 zeros. Since the word "billion" refers to different amounts in different parts of the world, its abbreviations can likewise vary. The international abbreviation for billion is "G," as in $3G to indicate $3 billion.