Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, BEGINNING OF PERIOD	$ 20,536	$ 13,851	$ 21,856	$ 19,934	$ 13,960	$ 14,124
OPERATING ACTIVITIES:
Net income	2,883	256	7,046	1,176	8,902	1,926
Adjustments to reconcile net income to net cash from operating activities:
Depreciation of property and equipment, including internal-use software and website development, and other amortization, including capitalized content costs	3,778	2,912	11,079	7,980	14,577	10,277
Stock-based compensation	1,350	1,085	4,001	3,036	5,180	3,923
Other operating expense, net	62	43	202	146	258	177
Other expense (income), net	96	(128)	22	(288)	17	(267)
Deferred income taxes	266	(74)	268	279	(40)	(2)
Changes in operating assets and liabilities:
Inventories	(1,094)	(1,593)	36	(1,328)	(2,220)	(2,371)
Accounts receivable, net and other	(2,884)	(1,760)	(3,220)	(2,016)	(5,983)	(3,938)
Accounts payable	3,894	2,974	(3,618)	(1,803)	5,285	5,479
Accrued expenses and other	237	(122)	(2,193)	(1,778)	(131)	476
Unearned revenue	0	184	623	603	759	1,316
Net cash provided by (used in) operating activities	8,588	3,777	14,246	6,007	26,604	16,996
INVESTING ACTIVITIES:
Purchases of property and equipment, including internal-use software and website development	3,352	3,074	9,693	8,336	13,312	10,750
Proceeds from property and equipment incentives	825	415	1,490	1,314	2,073	1,723
Acquisitions, net of cash acquired, and other	(976)	(13,213)	(1,855)	(13,891)	(1,936)	(13,893)
Sales and maturities of marketable securities	1,964	2,211	6,301	6,191	9,787	7,384
Purchases of marketable securities	(4,033)	(4,817)	(5,040)	(10,381)	(7,390)	(13,633)
Net cash provided by (used in) investing activities	(5,572)	(18,478)	(8,797)	(25,103)	(10,778)	(29,169)
FINANCING ACTIVITIES:
Proceeds from long-term debt and other	143	16,049	363	16,119	472	16,653
Repayments of long-term debt and other	(183)	(71)	(533)	(159)	(1,675)	(217)
Principal repayments of capital lease obligations	(2,247)	(1,267)	(5,544)	(3,327)	(7,016)	(4,331)
Principal repayments of finance lease obligations	(82)	(49)	(211)	(134)	(277)	(175)
Net cash provided by (used in) financing activities	(2,369)	14,662	(5,925)	12,499	(8,496)	11,930
Foreign currency effect on cash, cash equivalents, and restricted cash	(151)	148	(348)	623	(258)	79
Net increase (decrease) in cash, cash equivalents, and restricted cash	496	109	(824)	(5,974)	7,072	(164)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH, END OF PERIOD	21,032	13,960	21,032	13,960	21,032	13,960
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest on long-term debt	283	5	733	155	907	299
Cash paid for interest on capital and finance lease obligations	165	112	419	235	503	296
Cash paid for income taxes, net of refunds	200	172	1,013	865	1,106	960
Property and equipment acquired under capital leases	2,329	2,256	6,934	6,867	9,704	8,905
Property and equipment acquired under build-to-suit leases	$ 962	$ 750	$ 2,498	$ 2,698	$ 3,340	$ 3,114