Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	[1]
Preferred stock, no par value	$ 0	$ 0
Preferred stock, authorized	1,000,000.0	1,000,000.0
Preferred stock, issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized	1,200,000,000	1,200,000,000
Common stock, issued	346,400,000	346,300,000
Treasury stock, shares	700,000
Truck, Parts and Other
Marketable debt securities, amortized cost	$ 1,091,000,000.0	$ 1,154,000,000.0
Marketable debt securities, allowance	$ 0	$ 0

[1] The December 31, 2019 consolidated balance sheet has been derived from audited financial statements.