How much cash can I fly with?

I'm planning a trip soon and I'm wondering about the rules regarding carrying cash on flights. Could you tell me, how much cash am I allowed to fly with? Are there any specific restrictions or regulations that I should be aware of? I'm interested in both domestic and international flights, so if there are different rules for each, please let me know. Additionally, are there any security measures or screening processes that I should expect when carrying a significant amount of cash on a flight? Thank you for your help with this question.