Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating Activities:
Net income (loss)	$ (1,808)	$ 3,843
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation expense	136	120
Amortization expense	562	587
Stock-based compensation expense	309	317
Acquired in-process research and development expenses	4,621	291
Deferred income taxes	109	28
Net unrealized (gain) loss from equity securities	82	(254)
Other	130	81
Changes in operating assets and liabilities:
Accounts receivable, net	368	(68)
Inventories	(22)	(12)
Prepaid expenses and other	76	(34)
Accounts payable	(113)	(166)
Income taxes payable	(361)	(274)
Accrued liabilities and other	(87)	(540)
Net cash provided by operating activities	4,002	3,919
Investing Activities:
Purchases of marketable debt securities	(16,753)	(17,022)
Proceeds from sales of marketable debt securities	10,426	1,564
Proceeds from maturities of marketable debt securities	6,227	10,029
Acquisitions, including in-process research and development, net of cash acquired	(4,804)	(239)
Purchases of equity securities	(86)	(104)
Capital expenditures	(314)	(422)
Other	(63)	(213)
Net cash used in investing activities	(5,367)	(6,407)
Financing Activities:
Proceeds from issuances of common stock	212	141
Repurchases of common stock	(1,382)	(1,422)
Repayments of debt and other obligations	(500)	(1,250)
Payments of dividends	(1,730)	(1,617)
Other	(85)	(75)
Net cash used in financing activities	(3,485)	(4,223)
Effect of exchange rate changes on cash and cash equivalents	(35)	11
Net change in cash and cash equivalents	(4,885)	(6,700)
Cash and cash equivalents at beginning of period	11,631	17,940
Cash and cash equivalents at end of period	$ 6,746	$ 11,240