Operating Financial Information for Reportable Segments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Operating Revenues	$ 29,420	$ 28,242
Operating income	6,222	5,195
Wireless
Segment Reporting Information [Line Items]
Operating Revenues	19,523	18,273
Operating income	6,418	5,217
Wireline
Segment Reporting Information [Line Items]
Operating Revenues	9,830	9,945
Operating income	13	157
Total Segments
Segment Reporting Information [Line Items]
Operating Revenues	29,353	28,218
Operating income	6,431	5,374
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Operating Revenues	67	24
Operating income	(209)	(179)
Reconciling Items
Segment Reporting Information [Line Items]
Operating income	(209)	(179)
External Operating Revenues
Segment Reporting Information [Line Items]
Segment reporting information, revenue	29,420	28,242
External Operating Revenues | Wireless
Segment Reporting Information [Line Items]
Segment reporting information, revenue	19,496	18,250
External Operating Revenues | Wireless | Service Revenue Retail Service
Segment Reporting Information [Line Items]
Segment reporting information, revenue	16,155	14,872
External Operating Revenues | Wireless | Service Revenue Other Service
Segment Reporting Information [Line Items]
Segment reporting information, revenue	557	524
External Operating Revenues | Wireless | Service Revenue
Segment Reporting Information [Line Items]
Segment reporting information, revenue	16,712	15,396
External Operating Revenues | Wireless | Equipment
Segment Reporting Information [Line Items]
Segment reporting information, revenue	1,809	1,835
External Operating Revenues | Wireless | Other
Segment Reporting Information [Line Items]
Segment reporting information, revenue	975	1,019
External Operating Revenues | Wireline
Segment Reporting Information [Line Items]
Segment reporting information, revenue	9,559	9,666
External Operating Revenues | Wireline | Mass Markets Consumer Retail
Segment Reporting Information [Line Items]
Segment reporting information, revenue	3,590	3,441
External Operating Revenues | Wireline | Mass Markets Small Business
Segment Reporting Information [Line Items]
Segment reporting information, revenue	648	659
External Operating Revenues | Wireline | Mass Markets
Segment Reporting Information [Line Items]
Segment reporting information, revenue	4,238	4,100
External Operating Revenues | Wireline | Global Enterprise Strategic Services
Segment Reporting Information [Line Items]
Segment reporting information, revenue	2,087	1,969
External Operating Revenues | Wireline | Global Enterprise Core
Segment Reporting Information [Line Items]
Segment reporting information, revenue	1,660	1,882
External Operating Revenues | Wireline | Global Enterprise
Segment Reporting Information [Line Items]
Segment reporting information, revenue	3,747	3,851
External Operating Revenues | Wireline | Global Wholesale
Segment Reporting Information [Line Items]
Segment reporting information, revenue	1,471	1,592
External Operating Revenues | Wireline | Other
Segment Reporting Information [Line Items]
Segment reporting information, revenue	103	123
External Operating Revenues | Total Segments
Segment Reporting Information [Line Items]
Segment reporting information, revenue	29,055	27,916
External Operating Revenues | Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Segment reporting information, revenue	365	326
Intersegment Revenues | Wireless
Segment Reporting Information [Line Items]
Segment reporting information, revenue	27	23
Intersegment Revenues | Wireline
Segment Reporting Information [Line Items]
Segment reporting information, revenue	271	279
Intersegment Revenues | Total Segments
Segment Reporting Information [Line Items]
Segment reporting information, revenue	298	302
Intersegment Revenues | Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Segment reporting information, revenue	$ (298)	$ (302)