Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Cash receipts from customers	$ 284,219,000,000	$ 264,327,000,000	$ 248,393,000,000
Cash paid for inventory and prescriptions dispensed by retail network pharmacies	(165,783,000,000)	(158,636,000,000)	(149,655,000,000)
Insurance benefits paid	(63,598,000,000)	(55,124,000,000)	(52,242,000,000)
Cash paid to other suppliers and employees	(31,652,000,000)	(29,763,000,000)	(28,932,000,000)
Interest and investment income received	743,000,000	894,000,000	955,000,000
Interest paid	(2,469,000,000)	(2,904,000,000)	(2,954,000,000)
Income taxes paid	(3,195,000,000)	(2,929,000,000)	(2,717,000,000)
Net cash provided by operating activities	18,265,000,000	15,865,000,000	12,848,000,000
Cash flows from investing activities:
Proceeds from sales and maturities of investments	7,246,000,000	6,467,000,000	7,049,000,000
Purchases of investments	(9,963,000,000)	(9,639,000,000)	(7,534,000,000)
Purchases of property and equipment	(2,520,000,000)	(2,437,000,000)	(2,457,000,000)
Proceeds from sale-leaseback transactions	0	101,000,000	5,000,000
Acquisitions (net of cash acquired)	(146,000,000)	(866,000,000)	(444,000,000)
Proceeds from sale of subsidiary	0	840,000,000	0
Other	122,000,000	0	42,000,000
Net cash used in investing activities	(5,261,000,000)	(5,534,000,000)	(3,339,000,000)
Cash flows from financing activities:
Net repayments of short-term debt	0	0	(720,000,000)
Proceeds from issuance of long-term debt	987,000,000	9,958,000,000	3,736,000,000
Repayments of long-term debt	(10,254,000,000)	(15,631,000,000)	(8,336,000,000)
Derivative settlements	0	(7,000,000)	(25,000,000)
Dividends paid	(2,625,000,000)	(2,624,000,000)	(2,603,000,000)
Proceeds from exercise of stock options	549,000,000	264,000,000	210,000,000
Payments for taxes related to net share settlement of equity awards	(168,000,000)	(88,000,000)	(112,000,000)
Other	155,000,000	432,000,000	196,000,000
Net cash used in financing activities	(11,356,000,000)	(7,696,000,000)	(7,654,000,000)
Net increase in cash, cash equivalents and restricted cash	1,648,000,000	2,635,000,000	1,855,000,000
Cash, cash equivalents and restricted cash at the beginning of the period	11,043,000,000	8,408,000,000	6,553,000,000
Cash, cash equivalents and restricted cash at the end of the period	12,691,000,000	11,043,000,000	8,408,000,000
Reconciliation of net income to net cash provided by operating activities:
Net income	7,898,000,000	7,192,000,000	6,631,000,000
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	4,512,000,000	4,441,000,000	4,371,000,000
Store impairments	1,358,000,000	0	231,000,000
Goodwill impairment	431,000,000	0	0
Stock-based compensation	484,000,000	400,000,000	453,000,000
(Gain) loss on sale of subsidiaries	0	(269,000,000)	205,000,000
Loss on early extinguishment of debt	452,000,000	1,440,000,000	79,000,000
Deferred income taxes	(428,000,000)	(570,000,000)	(654,000,000)
Other noncash items	(390,000,000)	72,000,000	33,000,000
Change in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, net	(2,703,000,000)	(1,510,000,000)	(2,158,000,000)
Inventories	735,000,000	(973,000,000)	(1,075,000,000)
Other assets	(3,000,000)	364,000,000	(614,000,000)
Accounts payable and pharmacy claims and discounts payable	2,898,000,000	2,769,000,000	3,550,000,000
Health care costs payable and other insurance liabilities	169,000,000	(231,000,000)	320,000,000
Other liabilities	2,852,000,000	2,740,000,000	1,476,000,000
Net cash provided by operating activities	$ 18,265,000,000	$ 15,865,000,000	$ 12,848,000,000