A complete search of the internet has found these results:
I have no idea is the most popular phrase on the web.
"I have no idea" means that the speaker doesn't know at all. "I have no ideas" means the speaker cannot think of any ideas about something.
3,067,356 results on the web
I hope you realize I have no idea what I'm doing here.
I have no idea of the letters that I write.
I have no idea what parker is now.
I have no idea what I'm doing in court.
I have no idea why I keep saying that.
I have no idea, but I'll look everywhere.
I have no idea what crime I've committed.
I have no idea where I should be.
But then again** I have no idea** why I'm here.
I'm afraid I have no idea.
I have no idea. I was bluffing.
Obviously I have no idea what I'm doing.
I can honestly say I have no idea.
1,205,502 results on the web
I would tell you what to do exactly, but I have no ideas at this point.
He never has any ideas for games.
Do you have any ideas for what to wear for Halloween?
No, I haven't thought of any ideas of what to wear.
They told everyone that I have no good ideas.
Everyone knows that I have no ideas when it comes to sales strategy.