If you're in an accident for which nobody else is at fault, or your vehicle is damaged by a factor outside of your control (hail, fire, theft, etc.), and you have collision and comprehensive insurance, your insurance company will cover the costs to bring your vehicle back to its pre-accident condition.
Since collision and comprehensive insurance apply to losses to your vehicle, the limit of this coverage is, basically, the market value of the vehicle.
If the cost to repair damages exceeds a pre-determined percentage of the vehicle's value (usually 80%), the insurance company will declare the vehicle "totaled" and pay the policy holder 100% of the vehicle's value.
Everything else being equal, comprehensive and collision policies on higher-value vehicles (whose limits are naturally higher) are higher than comprehensive and collision policies on lower-value vehicles.