Segment Information - Reconciliation of Segments Operating Income to Consolidated Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Operating income	$ 6,617	$ 8,014	$ 13,966	$ 14,976
Severance charges (Note 8)	(339)	(195)	(339)	(195)
Other components of net periodic benefit cost (income) (Note 8)	(254)	(219)	(509)	(437)
Gain on spectrum license transaction (Note 3)	0	0	0	126
Acquisition and integration related charges (Note 3)	(120)	(564)	(227)	(564)
Product realignment charges	(451)	0	(451)	0
Operating results from divested businesses	0	45	0	132
Equity in losses of unconsolidated businesses	(228)	(28)	(247)	(49)
Other income (expense), net	360	199	285	(428)
Interest expense	(1,222)	(1,218)	(2,423)	(2,350)
Income Before Provision For Income Taxes	5,527	6,967	11,581	12,149
Operating Segments
Segment Reporting Information [Line Items]
Operating income	8,255	7,457	16,373	14,739
Corporate and other
Segment Reporting Information [Line Items]
Operating income	$ (474)	$ (284)	$ (881)	$ (599)