CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 901	$ 887
Property and equipment, accumulated depreciation and amortization (in dollars)	4,538	4,323
Other intangible assets, accumulated amortization (in dollars)	$ 701	$ 659
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	147,692,493	146,920,454
Common stock in treasury, shares	48,424,273	48,425,298