Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 2,311	$ 2,071
Depreciation and amortization	471	524
Share-based compensation expense	54	60
Deferred income taxes	(72)	(77)
Other items, net	44	15
Changes in operating assets and liabilities, net of acquisitions:
Trade receivables, net	(384)	(47)
Inventories	(107)	(125)
Other assets	(135)	(155)
Accounts payable	(278)	(20)
Accrued income taxes, net	353	268
Long-term tax liability	63	124
Other liabilities	407	(253)
Net cash provided by operating activities	2,727	2,385
Cash flows from investing activities:
Purchases of marketable securities	(2,732)	(7,077)
Proceeds from sales of marketable securities	16,694	5,612
Proceeds from maturities of marketable securities	900	1,528
Cash acquired in acquisition, net of cash paid	197	0
Purchases of property, plant and equipment	(155)	(168)
Other	2	(52)
Net cash provided by (used in) investing activities	14,906	(157)
Cash flows from financing activities:
Repayment of debt	0	(605)
Repurchases of common stock	(10,697)	(586)
Dividends paid	(951)	(847)
Other	(44)	(73)
Net cash used in financing activities	(11,692)	(2,111)
Increase in cash and cash equivalents	5,941	117
Cash and cash equivalents at beginning of period	3,800	3,241
Cash and cash equivalents at end of period	$ 9,741	$ 3,358