Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts
Beginning balance	$ 119	$ 119	$ 105
Net (credits) charges to expenses		9	15
Utilization of allowances	(18)	(11)	(16)
Ending balance	98	119	119
Trade accounts receivable, net
Accounts receivable	1,645	1,591
Less: allowance for doubtful accounts	(68)	(73)
Less: allowance for sales returns	(30)	(46)
Trade accounts receivable, net	1,548	1,472
Property, plant and equipment, net
Land	102	91
Buildings and improvements	1,120	981
Equipment, furniture and fixtures	3,183	2,955
Capital in progress	219	338
Property, plant and equipment	4,625	4,365
Less: accumulated depreciation	2,928	2,735
Property, plant and equipment, net	1,697	1,630	1,490
Accrued expenses
Legal reserves	1,176	1,062
Payroll and related liabilities	591	572
Accrued contingent consideration	36	63
Other accrued expenses	653	615
Accrued expenses	2,456	2,312
Other long-term liabilities
Accrued income taxes	1,275	781
Legal reserves	436	961
Accrued contingent consideration	133	141
Other	525	455
Other long-term liabilities	2,370	2,338
Allowance for Doubtful Accounts [Member]
Allowance for doubtful accounts
Beginning balance	73	75	76
Net (credits) charges to expenses	14	9	15
Utilization of allowances		(11)	(16)
Ending balance	$ 68	$ 73	$ 75