Faustus movin' right along...
According to this, there are two kinds of lightning: negative and positive.
An average bolt of negative lightning carries a current of 30-to-50 kiloamperes(kA), although some bolts can be up to 120kA, and transfers a charge of 5 coulombs and 500 megajoules (enough to light a 100 watt light bulb for 2 months).
Positive lightning makes up less than 5% of all lightning. It occurs when the leader forms at the positively charged cloud tops, with the consequence that a negatively charged streamer issues from the ground. An average bolt of positive lightning carries a current of up to 300 kiloamperes (about ten times as much current as a bolt of negative lightning), transfers a charge of up to 300 coulombs, has a potential difference up to 1 gigavolt (a billion volts), lasts for hundreds of milliseconds, and dissipates enough energy to light a 100 watt lightbulb for up to 95 years.