Segment Information Reportable Segments and Reconciliation to Consolidated Net Income (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) Segment	Mar. 31, 2016 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Segment Reporting Disclosure [Line Items]
Number of Reportable Segments | Segment	3
Net sales	$ 35,714	$ 29,128
Operating expenses	34,709	28,057
Operating income	1,005	1,071
Total non-operating income (expense)	(52)	(15)
Provision for income taxes	(229)	(475)
Equity-method investment activity, net of tax	0	(68)
Net income	724	513	$ 2,583	$ 1,166
Operating Segments
Segment Reporting Disclosure [Line Items]
Net sales	35,714	29,128
Operating expenses	34,709	28,057
North America | Operating Segments
Segment Reporting Disclosure [Line Items]
Net sales	20,992	16,996
Operating expenses	20,396	16,408
Operating income	596	588
International | Operating Segments
Segment Reporting Disclosure [Line Items]
Net sales	11,061	9,566
Operating expenses	11,542	9,687
Operating income	(481)	(121)
AWS | Operating Segments
Segment Reporting Disclosure [Line Items]
Net sales	3,661	2,566
Operating expenses	2,771	1,962
Operating income	$ 890	$ 604