A deal between Johnson Controls and Tyco, which have market capitalizations of $23 billion and $13 billion respectively, would provide the clearest indication yet that the recent market volatility has not derailed strategic mergers from advancing. Johnson Controls and Tyco did not respond to requests for comment. The deal would come as Milwaukee, Wisconsin-based Johnson Controls was preparing to spin off its automotive seating and interiors business, to focus on its building efficiency and automotive battery operations.