Operating Financial Information for Reportable Segments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Operating Revenues	$ 30,279	$ 29,007	$ 89,485	$ 85,801
Operating income	7,128	5,483	19,905	16,329
Wireless
Segment Reporting Information [Line Items]
Operating Revenues	20,399	19,024	59,898	55,874
Operating income	6,886	6,047	19,768	16,977
Wireline
Segment Reporting Information [Line Items]
Operating Revenues	9,814	9,914	29,378	29,790
Operating income	155	41	242	386
Total Segments
Segment Reporting Information [Line Items]
Operating Revenues	30,213	28,938	89,276	85,664
Operating income	7,041	6,088	20,010	17,363
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Operating Revenues	66	69	209	137
Operating income	(191)	(221)	(620)	(650)
Reconciling Items
Segment Reporting Information [Line Items]
Operating income	87	(605)	(105)	(1,034)
External Operating Revenues
Segment Reporting Information [Line Items]
Operating Revenues	30,279	29,007	89,485	85,801
External Operating Revenues | Wireless
Segment Reporting Information [Line Items]
Operating Revenues	20,374	19,002	59,822	55,807
External Operating Revenues | Wireless | Service Revenue Retail Service
Segment Reporting Information [Line Items]
Operating Revenues	16,764	15,523	49,327	45,610
External Operating Revenues | Wireless | Service Revenue Other Service
Segment Reporting Information [Line Items]
Operating Revenues	737	616	1,950	1,684
External Operating Revenues | Wireless | Service Revenue
Segment Reporting Information [Line Items]
Operating Revenues	17,501	16,139	51,277	47,294
External Operating Revenues | Wireless | Equipment
Segment Reporting Information [Line Items]
Operating Revenues	1,921	1,855	5,679	5,456
External Operating Revenues | Wireless | Other
Segment Reporting Information [Line Items]
Operating Revenues	952	1,008	2,866	3,057
External Operating Revenues | Wireline
Segment Reporting Information [Line Items]
Operating Revenues	9,546	9,632	28,574	28,952
External Operating Revenues | Wireline | Mass Markets Consumer Retail
Segment Reporting Information [Line Items]
Operating Revenues	3,709	3,554	10,941	10,473
External Operating Revenues | Wireline | Mass Markets Small Business
Segment Reporting Information [Line Items]
Operating Revenues	650	667	1,945	1,990
External Operating Revenues | Wireline | Mass Markets
Segment Reporting Information [Line Items]
Operating Revenues	4,359	4,221	12,886	12,463
External Operating Revenues | Wireline | Global Enterprise Strategic Services
Segment Reporting Information [Line Items]
Operating Revenues	2,112	2,010	6,278	5,962
External Operating Revenues | Wireline | Global Enterprise Core
Segment Reporting Information [Line Items]
Operating Revenues	1,551	1,769	4,760	5,488
External Operating Revenues | Wireline | Global Enterprise
Segment Reporting Information [Line Items]
Operating Revenues	3,663	3,779	11,038	11,450
External Operating Revenues | Wireline | Global Wholesale
Segment Reporting Information [Line Items]
Operating Revenues	1,412	1,512	4,320	4,666
External Operating Revenues | Wireline | Other
Segment Reporting Information [Line Items]
Operating Revenues	112	120	330	373
External Operating Revenues | Total Segments
Segment Reporting Information [Line Items]
Operating Revenues	29,920	28,634	88,396	84,759
External Operating Revenues | Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Operating Revenues	359	373	1,089	1,042
Intersegment Revenues | Wireless
Segment Reporting Information [Line Items]
Operating Revenues	25	22	76	67
Intersegment Revenues | Wireline
Segment Reporting Information [Line Items]
Operating Revenues	268	282	804	838
Intersegment Revenues | Total Segments
Segment Reporting Information [Line Items]
Operating Revenues	293	304	880	905
Intersegment Revenues | Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Operating Revenues	$ (293)	$ (304)	$ (880)	$ (905)