Consolidated Balance Sheets, as of December 31 (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 35	$ 40
Other receivables, allowances	$ 44	$ 47
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	5,000,000,000	5,000,000,000
Common stock, shares issued (in shares)	1,996,537,778	1,996,537,778
Treasury stock, at cost, shares (in shares)	561,531,524	545,537,923