AM Best has affirmed the Financial Strength Rating of A++ and the Long-Term Issuer Credit Rating of“ aa+” of Berkshire Hathaway Life Insurance Company of Nebraska. In addition, AM Best has affirmed the FSR of A+ and the Long-Term ICR of“ aa-” of First Berkshire Hathaway Life Insurance Company. The company’ s core net investment income moderated slightly to $717.6 million…