What are the units? 10^14 is indeed far too much if it's seconds, but might not be beyond reason for a set of size 10 million if it's nanoseconds (then you have a bit under three hours.) So think about which units this would actually have.
Indeed, an algorithm being in P may not be sufficient to scale, but if a problem is NP-complete (assuming P != NP) there's almost certainly no scalable algorithm for it.
(10^14) nanoseconds = 1.1574 days
I should have said If N^2 means 10 million... Anyway, I tend to think of 10^10 nanoseconds as vary bad (10 seconds) and (10^14) > 1 day as unreasonable, but that's just a rule of thumb from the days of 1Ghz CPUS's.
N^2 means 10 million is not acceptable in a reasonable amount of time. (10^14)
N^6 hit's 10^14 at 216.
N^log N hit's 10^14 a little after 5500 [edit 5517] and it takes 1,000,001 before it's worse than N^6 but it's all downhill from there.