Segment Information - Operating Financial Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 33,485	$ 32,981
Depreciation and amortization expense	4,577	4,445
Total Operating Expenses	25,507	25,460
Operating Income	7,978	7,521
Service
Segment Reporting Information [Line Items]
Cost of wireless equipment	6,950	6,967
Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	5,398	5,361
Cost of wireless equipment	6,106	5,905
Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	28,087	27,620
Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	3,206	3,207
Wireless service
Segment Reporting Information [Line Items]
Operating revenues	20,764	20,227
Consumer | Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	2,896	2,896
Consumer | Wireless service
Segment Reporting Information [Line Items]
Operating revenues	17,199	16,760
Business | Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	310	311
Business | Wireless service
Segment Reporting Information [Line Items]
Operating revenues	3,565	3,467
Operating Segments Excluding Intersegment Elimination | Service
Segment Reporting Information [Line Items]
Operating revenues	19,993	19,572
Operating Segments Excluding Intersegment Elimination | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	4,532	4,490
Operating Segments Excluding Intersegment Elimination | Other
Segment Reporting Information [Line Items]
Operating revenues	1,020	943
Operating Segments Excluding Intersegment Elimination | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	3,457	3,587
Operating Segments Excluding Intersegment Elimination | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	3,307	3,190
Operating Segments Excluding Intersegment Elimination | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	515	590
Operating Segments Excluding Intersegment Elimination | Consumer | Service
Segment Reporting Information [Line Items]
Operating revenues	19,993	19,572
Operating Segments Excluding Intersegment Elimination | Consumer | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	4,532	4,490
Operating Segments Excluding Intersegment Elimination | Consumer | Other
Segment Reporting Information [Line Items]
Operating revenues	1,020	943
Operating Segments Excluding Intersegment Elimination | Consumer | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Consumer | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Consumer | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Business | Service
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Business | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Business | Other
Segment Reporting Information [Line Items]
Operating revenues	0	0
Operating Segments Excluding Intersegment Elimination | Business | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	3,457	3,587
Operating Segments Excluding Intersegment Elimination | Business | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	3,307	3,190
Operating Segments Excluding Intersegment Elimination | Business | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	515	590
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues	80	61
Intersegment Eliminations | Consumer
Segment Reporting Information [Line Items]
Operating revenues	73	52
Intersegment Eliminations | Business
Segment Reporting Information [Line Items]
Operating revenues	7	9
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	32,904	32,433
Cost of wireless equipment	6,106	5,905
Centrally managed network and shared service costs	7,003	7,054
Depreciation and amortization expense	4,563	4,437
Other segment expenses	7,144	7,266
Total Operating Expenses	24,816	24,662
Operating Income	8,088	7,771
Operating Segments | Consumer
Segment Reporting Information [Line Items]
Operating revenues	25,618	25,057
Cost of wireless equipment	4,912	4,750
Centrally managed network and shared service costs	4,521	4,430
Depreciation and amortization expense	3,543	3,309
Other segment expenses	5,218	5,196
Total Operating Expenses	18,194	17,685
Operating Income	7,424	7,372
Operating Segments | Business
Segment Reporting Information [Line Items]
Operating revenues	7,286	7,376
Cost of wireless equipment	1,194	1,155
Centrally managed network and shared service costs	2,482	2,624
Depreciation and amortization expense	1,020	1,128
Other segment expenses	1,926	2,070
Total Operating Expenses	6,622	6,977
Operating Income	664	399
Operating Segments | Business | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	866	871
Operating Segments | Business | Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	$ 6,400	$ 6,500