Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets
Trade receivables, reserves (in dollars)	$ 16	$ 17
Common stock, per share par value (in dollars per share)	$ 0.20	$ 0.20
Common stock, authorized shares	1,100,000,000	1,100,000,000
Common stock, outstanding shares	892,214,604	891,360,091
Treasury stock, shares	127,977,306	127,681,335