TOOLS & SETTINGS.
Click Get search volume and forecast.
Type your competitor’s keyword(s) that show their ads on top of your ads, for example, ‘cordless drill’.
Click GET STARTED.
Click HISTORICAL METRICS.
The Keyword Planner will not show your competitors’ bids, but it will give you an estimation of impressions, clicks, conversions, cost, average CPC, etc.
Watch it on YouTube (Larger version)
Extract from my Book ‘Making Google Ads Work’.