Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Cash Flows [Abstract]
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	$ 13,203	$ 12,521	$ 19,334	$ 15,890	$ 13,656	$ 10,709
OPERATING ACTIVITIES:
Net income	256	252	1,176	1,622	1,926	2,105
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	2,912	2,084	7,980	5,819	10,277	7,572
Stock-based compensation	1,085	776	3,036	2,088	3,923	2,694
Other operating expense, net	43	31	146	128	177	163
Other expense (income), net	(128)	(23)	(288)	(41)	(267)	39
Deferred income taxes	(74)	(81)	279	36	(2)	226
Changes in operating assets and liabilities:
Inventories	(1,593)	(1,095)	(1,328)	(383)	(2,371)	(1,726)
Accounts receivable, net and other	(1,758)	(671)	(2,005)	(1,443)	(3,929)	(2,621)
Accounts payable	3,046	2,540	(1,731)	(2,252)	5,551	3,887
Accrued expenses and other	(122)	441	(1,778)	(531)	476	1,306
Additions to unearned revenue	3,762	2,802	10,862	7,956	14,837	10,377
Amortization of previously unearned revenue	(3,578)	(2,397)	(10,259)	(6,715)	(13,521)	(9,018)
Net cash provided by (used in) operating activities	3,851	4,659	6,090	6,284	17,077	15,004
INVESTING ACTIVITIES:
Purchases of property and equipment, including internal-use software and website development, net	(2,659)	(1,841)	(7,022)	(4,731)	(9,027)	(6,040)
Acquisitions, net of cash acquired, and other	(13,213)	(84)	(13,891)	(113)	(13,893)	(430)
Sales and maturities of marketable securities	2,221	1,431	6,424	3,500	7,656	4,635
Purchases of marketable securities	(5,469)	(2,076)	(11,298)	(4,358)	(14,697)	(5,717)
Net cash provided by (used in) investing activities	(19,120)	(2,570)	(25,787)	(5,702)	(29,961)	(7,552)
FINANCING ACTIVITIES:
Proceeds from long-term debt and other	16,080	8	16,170	83	16,707	176
Repayments of long-term debt and other	(79)	(26)	(202)	(271)	(285)	(1,212)
Principal repayments of capital lease obligations	(1,267)	(938)	(3,327)	(2,855)	(4,331)	(3,579)
Principal repayments of finance lease obligations	(49)	(44)	(134)	(105)	(175)	(131)
Net cash provided by (used in) financing activities	14,685	(1,000)	12,507	(3,148)	11,916	(4,746)
Foreign currency effect on cash and cash equivalents	148	46	623	332	79	241
Net increase (decrease) in cash and cash equivalents	(436)	1,135	(6,567)	(2,234)	(889)	2,947
CASH AND CASH EQUIVALENTS, END OF PERIOD	12,767	13,656	12,767	13,656	12,767	13,656
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest on long-term debt	5	1	155	146	299	295
Cash paid for interest on capital and finance lease obligations	112	50	235	145	296	188
Cash paid for income taxes, net of refunds	172	91	865	317	960	390
Property and equipment acquired under capital leases	2,256	1,369	6,867	3,666	8,905	4,998
Property and equipment acquired under build-to-suit leases	$ 750	$ 211	$ 2,698	$ 793	$ 3,114	$ 956