Segment Information - Reportable Segments and Reconciliation to Consolidated Net Income (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) segment	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			3
Segment Reporting Disclosure [Line Items]
Net sales	$ 52,886	$ 37,955	$ 103,928	$ 73,669
Operating expenses	49,903	37,327	99,017	72,037
Operating income (loss)	2,983	628	4,911	1,632
Total non-operating income (expense)	(378)	38	(391)	(14)
Provision for income taxes	(74)	(467)	(361)	(695)
Equity-method investment activity, net of tax	3	(2)	4	(2)
Net income	2,534	197	4,163	921	$ 6,275	$ 1,922
North America
Segment Reporting Disclosure [Line Items]
Net sales	32,169	22,370	62,894	43,362
Operating expenses	30,334	21,934	59,910	42,330
Operating income (loss)	1,835	436	2,984	1,032
International
Segment Reporting Disclosure [Line Items]
Net sales	14,612	11,485	29,487	22,546
Operating expenses	15,106	12,209	30,603	23,752
Operating income (loss)	(494)	(724)	(1,116)	(1,206)
AWS
Segment Reporting Disclosure [Line Items]
Net sales	6,105	4,100	11,547	7,761
Operating expenses	4,463	3,184	8,504	5,955
Operating income (loss)	$ 1,642	$ 916	$ 3,043	$ 1,806