Fitch

AAA = Exceptionally Strong
AA+, AA, AA- = Very Strong
A+, A, A- = Strong
BBB+,BBB,BBB- = Good
BB+,BB,BB- = Moderately Weak
B+, B, B- = Weak
CCC+, CCC, CCC-, CC, C = Very Weak

If you are also interested in system ratings of other companies, just visit their website or contact them.
There's also a system used by Federal supervisory agencies called UFIRS known as the CAMELS rating system and you can read about it in our 'CAMELS Rating system' menu selection.