Consolidated Condensed Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 103	$ 132
Accumulated depreciation	(6,534)	(6,780)
Accumulated amortization	$ 520	$ 673
Common stock, par value (in USD per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	113,000,000	113,000,000
Common stock, shares outstanding (in shares)	63,000,000	63,000,000
Treasury stock (in shares)	51,000,000	50,000,000