Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock par value	$ 1.00	$ 1.00	$ 1.00
Common stock shares authorized	40,000,000	40,000,000	40,000,000
Common stock shares issued	37,165,854	37,140,854	37,115,854
Common stock shares outstanding	37,165,854	37,140,854	37,115,854