it depends on your type, but typically, for an A320 at standard load and standard weather (STD temp 1013hPa, ...)you'll get:
4° angle of descent at 340 kts/Mach 0.80
3° angle of descent at 250 kts/Mach 0.76
you have to factor in the wind, about 10% correction for 50kt component, and eng anti ice. finally most places and companies now require 250kts under FL100.
so for you're example, no wind, it's about 75 miles from FL370 down to FL100 (270/4 + 5 miles reduction from 340 to 250 kts)
then about 35 miles under FL100, not counting the deceleration.
typically, level flight will give you 5 miles from 250kts to 180 kts
seb