cool-headed; level-headed; hard-headed
Describes a person or attitude that is calm, rational, and unswayed by emotion, often in a way that can seem cold or ruthless.
He rebuilt the company with cool-headed decisions.
We need to look at reality with a level-headed gaze.
He made the decision to lay off staff with cool, rational judgment.
She viewed the reality with a cold, detached eye.
He analyzed the situation with cool, dispassionate reasoning.