Segment Information - Reconciliation of Segments Operating Income to Consolidated Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Operating income	$ 7,361	$ 7,850	$ 13,940	$ 15,559
Other components of net periodic benefit charges	(204)	(203)	(407)	(406)
Loss on spectrum license transaction	0	0	(1,195)	0
Equity in losses of unconsolidated businesses	(13)	(13)	(25)	(19)
Other income (expense), net	(72)	(1,312)	71	(1,017)
Interest expense	(1,089)	(1,215)	(2,123)	(2,425)
Income Before Provision For Income Taxes	6,187	5,310	11,863	12,098
Operating Segments
Segment Reporting Information [Line Items]
Operating income	8,010	8,407	16,246	16,705
Corporate and other
Segment Reporting Information [Line Items]
Operating income	$ (445)	$ (354)	$ (704)	$ (740)