Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Cash receipts from customers	$ 43,369	$ 43,913
Cash paid for inventory and prescriptions dispensed by retail network pharmacies	(36,195)	(36,178)
Cash paid to other suppliers and employees	(4,271)	(3,823)
Interest received	50	6
Interest paid	(545)	(328)
Income taxes paid	(53)	(57)
Net cash provided by operating activities	2,355	3,533
Cash flows from investing activities:
Purchases of property and equipment	(482)	(457)
Proceeds from sale of property and equipment and other assets	2	5
Acquisitions (net of cash acquired) and other investments	(368)	(93)
Purchase of available-for-sale investments	(18)
Maturity of available-for-sale investments	10	8
Proceeds from sale of subsidiary	725
Net cash used in investing activities	(131)	(537)
Cash flows from financing activities:
Decrease in short-term debt	(1,276)	(106)
Proceeds from issuance of long-term debt	39,376
Repayments of long-term debt	(1)
Derivative settlements	446
Repurchase of common stock		(3,621)
Dividends paid	(508)	(516)
Proceeds from exercise of stock options	107	121
Payments for taxes related to net share settlement of equity awards	(4)	(11)
Net cash provided by (used in) financing activities	38,140	(4,133)
Net increase (decrease) in cash, cash equivalents and restricted cash	40,364	(1,137)
Cash, cash equivalents and restricted cash at the beginning of the period	1,900	3,520
Cash, cash equivalents and restricted cash at the end of the period	42,264	2,383
Reconciliation of net income to net cash provided by operating activities:
Net income	998	953
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	644	619
Stock-based compensation	55	55
Deferred income taxes and other noncash items	62	14
Change in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, net	(857)	48
Inventories	464	456
Other current assets	56	(74)
Other assets	(113)	(1)
Accounts payable and claims and discounts payable	(178)	(539)
Accrued expenses	1,231	1,848
Other long-term liabilities	(7)	154
Net cash provided by operating activities	$ 2,355	$ 3,533