Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts, accounts receivable	$ 333	$ 260
Allowance for doubtful accounts, other receivables	138	156
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	3,173	2,954
Finite-lived Intangible Assets, Accumulated Amortization	$ 3,128	$ 2,685
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	953	954
Common Stock, shares outstanding	953	954
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10	10
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0