Steak-n-Shake Chili

2 tablespoons oil
1 1/2 pounds ground beef
1/2 teaspoon salt
1 can onion soup
1 tablespoon chili powder
2 teaspoons ground cumin
1/2 teaspoon black pepper
2 teaspoons cocoa
2 cans kidney beans
1 (6 ounce) can tomato paste
1 (8 ounce) can tomato sauce
1 cup cola (Coca-Cola