CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 1,041	$ 1,031
Property and equipment, accumulated depreciation and amortization (in dollars)	4,926	4,974
Other intangible assets, accumulated amortization (in dollars)	$ 814	$ 772
Common stock, par value (in dollars per share)	$ 0.05	$ 0.05
Common stock, authorized shares	262,500,000	262,500,000
Common stock, shares issued	148,840,473	148,106,249
Common stock in treasury, shares	48,419,483	48,420,650