Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	300,000,000.0	300,000,000.0
Common stock, shares issued	93,400,000	93,400,000
Common stock, shares outstanding	82,000,000.0	83,000,000.0