STATEMENTS OF STOCKHOLDER'S EQUITY (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018	[1]	Mar. 31, 2018
Statement Of Stockholders Equity [Abstract]
Preferred stock, par value	$ 100	$ 100		$ 100
Common stock, par value	$ 100	$ 100		$ 100

[1] The December 31, 2018 balance sheet has been derived from audited financial statements.