Berkshire said Friday it generated $3.2 billion, or $2,087 per share, in net income. That's up significantly from last year's $1.1 billion, or $682 per share. Most of the swing in earnings is related to unrealized gains in the value of Berkshire's derivatives, some of which are tied to credit defaults and some of which are tied to equity markets. Berkshire owns more than 60 subsidiaries and it has