Big dogs housebreak faster than little dogs. This time of year is faster than winter months (because of cold wet weather) Sometimes really fast. My pup, who is 9 months now (he now weighs 8 1/2 pounds) took about 2 months to be completely trustworthy, Having a doggie door helps.
It depends on how much time you have to devote to the task. I am always home so I trained our pup in about two to three weeks. Previously with others it took longer since we were unable to stay constantly on watch. We had all our dogs crate trained though and that is a huge help. It keeps the house cleaner and life a bit more sane. as for big dogs vs. little dogs I have owned several of both from a teacup poodle to Belgian sheepdogs and it was all the same.
Took me six weeks to train my lab. I was very consistent with taking her outside every couple hours like you would a toddler to the toilet. I also crated her during they day and was able to come home at lunch. The more time you spend making sure they get outside the quicker you will achieve your goal.
It typically takes several weeks. Some breeds housebreak more quickly than others... If you have a purebred, check with a local breeder for specific tips. Crate training is the way to go, for housebreaking purposes and it has a variety of other benefits for your puppy and yourself! Have fun, and good luck.