To break that down a bit, it starts as a 6-year/$96 million extension that can escalate based on how far the Bengals advance in the playoffs, provided Dalton plays 80% of the regular season snaps ($1 million added to each subsequent year for reaching the Divisional Playoffs; $500,000 for reaching the Conference Championship; $1.5 million for reaching the Super Bowl).
And of that $96 million, only $17 million is fully guaranteed ($12 million signing bonus, $5 million roster bonus due on the third day of the 2015 league year). After that, it's essentially pay-as-you-go with a $200,000 workout bonus each year from 2016-2020.
Salaries by year:
2015: $3 million
2016: $10.5 million
2017: $13.1 million
2018: $13.7 million
2019: $16 million
2020: $17.5 million
Numbers come from Spotrac and Pro Football Talk.