CHICAGO--(BUSINESS WIRE)--Fitch Ratings has affirmed Aflac Inc.'s (Aflac) 'A' long-term Issuer Default Rating (IDR) and the 'A+' Insurance Financial Strength (IFS) ratings of Aflac's insurance subsidiaries. The Rating Outlook is Stable. A complete list of ratings appears at the end of this release. KEY RATING DRIVERS The affirmation of Aflac's ratings reflect the company's extremely strong competitive position in the supplemental accident and health insurance markets in Japan and the U.S., its