Consolidated Balance Sheet (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts, accounts receivable	$ 260	$ 196
Allowance for doubtful accounts, other receivables	156	169
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	2,954	2,675
Finite-lived Intangible Assets, Accumulated Amortization	$ 2,685	$ 2,283
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000	3,000
Common stock, shares issued	954	988
Common stock, shares outstanding	954	988
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