Step 1: Recall power formula.
\[
P = I^2 R
\]
Step 2: Consider doubling the current.
If the current becomes \(2I\), then power becomes:
\[
P' = (2I)^2 R = 4I^2R
\]
Step 3: Compare with original power.
Original power = \(P = I^2R\).
Thus,
\[
P' = 4P
\]
Step 4: Clarification about constant voltage.
Since \(V = IR\), doubling \(I\) would imply \(V\) changes. But if \(V\) is held constant externally, then \(I\) cannot double. However, as per the problem statement assumption, when current doubles, the mathematical relation yields \(P' = 4P\).
Final Answer:
\[
\boxed{4P}
\]