Segment Information - Operating Financial Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Operating revenues	$ 33,330	$ 33,336	$ 99,107	$ 98,844
Operating Income	5,926	7,473	21,265	22,277
Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	5,343	5,813	15,702	16,850
Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	27,987	27,523	83,405	81,994
Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	3,230	3,205	9,646	9,595
Wireless service
Segment Reporting Information [Line Items]
Operating revenues	19,843	19,330	59,129	57,332
Consumer \| Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	2,916	2,897	8,708	8,672
Consumer \| Wireless service
Segment Reporting Information [Line Items]
Operating revenues	16,377	15,963	48,853	47,324
Business \| Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	865	911	2,600	2,600
Business \| Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	6,500	6,600	19,400	19,900
Business \| Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	314	308	938	923
Business \| Wireless service
Segment Reporting Information [Line Items]
Operating revenues	3,466	3,367	10,276	10,008
Operating Segments Excluding Intersegment Elimination
Segment Reporting Information [Line Items]
Operating revenues	32,648	32,720	97,183	96,994
Operating Segments Excluding Intersegment Elimination \| Consumer
Segment Reporting Information [Line Items]
Operating revenues	25,305	25,202	75,182	74,516
Operating Segments Excluding Intersegment Elimination \| Consumer \| Service
Segment Reporting Information [Line Items]
Operating revenues	19,260	18,850	57,466	55,947
Operating Segments Excluding Intersegment Elimination \| Consumer \| Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	4,478	4,902	13,111	14,210
Operating Segments Excluding Intersegment Elimination \| Consumer \| Other
Segment Reporting Information [Line Items]
Operating revenues	1,567	1,450	4,605	4,359
Operating Segments Excluding Intersegment Elimination \| Business
Segment Reporting Information [Line Items]
Operating revenues	7,343	7,518	22,001	22,478
Operating Segments Excluding Intersegment Elimination \| Business \| Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	3,538	3,786	10,670	11,357
Operating Segments Excluding Intersegment Elimination \| Business \| Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	3,258	3,180	9,647	9,383
Operating Segments Excluding Intersegment Elimination \| Business \| Wholesale
Segment Reporting Information [Line Items]
Operating revenues	547	552	1,684	1,738
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues	63	64	188	182
Intersegment Eliminations \| Consumer
Segment Reporting Information [Line Items]
Operating revenues	55	55	162	156
Intersegment Eliminations \| Business
Segment Reporting Information [Line Items]
Operating revenues	8	9	26	26
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	32,711	32,784	97,371	97,176
Operating Income	8,169	8,086	24,044	23,599
Operating Segments \| Consumer
Segment Reporting Information [Line Items]
Operating revenues	25,360	25,257	75,344	74,672
Operating Income	7,604	7,547	22,580	21,976
Operating Segments \| Business
Segment Reporting Information [Line Items]
Operating revenues	7,351	7,527	22,027	22,504
Operating Income	$ 565	$ 539	$ 1,464	$ 1,623