Segment Information - Operating Financial Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 34,504	$ 32,796	$ 67,989	$ 65,777
Depreciation and amortization expense	4,635	4,483	9,212	8,928
Total Operating Expenses	26,332	24,978	51,839	50,438
Operating Income	8,172	7,818	16,150	15,339
Service
Segment Reporting Information [Line Items]
Cost of wireless equipment	6,878	6,904	13,828	13,871
Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	6,255	4,998	11,653	10,359
Cost of wireless equipment	7,007	5,567	13,113	11,472
Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	28,249	27,798	56,336	55,418
Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	3,234	3,209	6,440	6,416
Wireless service
Segment Reporting Information [Line Items]
Operating revenues	20,948	20,506	41,712	40,733
Consumer | Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	2,924	2,896	5,820	5,792
Consumer | Wireless service
Segment Reporting Information [Line Items]
Operating revenues	17,369	16,985	34,568	33,745
Business | Fios revenues
Segment Reporting Information [Line Items]
Operating revenues	310	313	620	624
Business | Wireless service
Segment Reporting Information [Line Items]
Operating revenues	3,579	3,521	7,144	6,988
Operating Segments Excluding Intersegment Elimination | Service
Segment Reporting Information [Line Items]
Operating revenues	20,186	19,797	40,179	39,369
Operating Segments Excluding Intersegment Elimination | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	5,369	4,143	9,901	8,633
Operating Segments Excluding Intersegment Elimination | Other
Segment Reporting Information [Line Items]
Operating revenues	1,019	932	2,039	1,875
Operating Segments Excluding Intersegment Elimination | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	3,435	3,545	6,892	7,132
Operating Segments Excluding Intersegment Elimination | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	3,339	3,199	6,646	6,389
Operating Segments Excluding Intersegment Elimination | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	494	547	1,009	1,137
Operating Segments Excluding Intersegment Elimination | Consumer | Service
Segment Reporting Information [Line Items]
Operating revenues	20,186	19,797	40,179	39,369
Operating Segments Excluding Intersegment Elimination | Consumer | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	5,369	4,143	9,901	8,633
Operating Segments Excluding Intersegment Elimination | Consumer | Other
Segment Reporting Information [Line Items]
Operating revenues	1,019	932	2,039	1,875
Operating Segments Excluding Intersegment Elimination | Consumer | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Consumer | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Consumer | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Business | Service
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Business | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Business | Other
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments Excluding Intersegment Elimination | Business | Enterprise and Public Sector
Segment Reporting Information [Line Items]
Operating revenues	3,435	3,545	6,892	7,132
Operating Segments Excluding Intersegment Elimination | Business | Business Markets and Other
Segment Reporting Information [Line Items]
Operating revenues	3,339	3,199	6,646	6,389
Operating Segments Excluding Intersegment Elimination | Business | Wholesale
Segment Reporting Information [Line Items]
Operating revenues	494	547	1,009	1,137
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues	81	64	161	125
Intersegment Eliminations | Consumer
Segment Reporting Information [Line Items]
Operating revenues	74	55	147	107
Intersegment Eliminations | Business
Segment Reporting Information [Line Items]
Operating revenues	7	9	14	18
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	33,923	32,227	66,827	64,660
Cost of wireless equipment	7,007	5,567	13,113	11,472
Centrally managed network and shared service costs	6,904	7,019	13,915	14,073
Depreciation and amortization expense	4,613	4,472	9,176	8,909
Other segment expenses	7,118	7,065	14,254	14,331
Total Operating Expenses	25,642	24,123	50,458	48,785
Operating Income	8,281	8,104	16,369	15,875
Operating Segments | Consumer
Segment Reporting Information [Line Items]
Operating revenues	26,648	24,927	52,266	49,984
Cost of wireless equipment	5,806	4,432	10,718	9,182
Centrally managed network and shared service costs	4,463	4,450	8,992	8,880
Depreciation and amortization expense	3,582	3,394	7,125	6,703
Other segment expenses	5,154	5,047	10,364	10,243
Total Operating Expenses	19,005	17,323	37,199	35,008
Operating Income	7,643	7,604	15,067	14,976
Operating Segments | Business
Segment Reporting Information [Line Items]
Operating revenues	7,275	7,300	14,561	14,676
Cost of wireless equipment	1,201	1,135	2,395	2,290
Centrally managed network and shared service costs	2,441	2,569	4,923	5,193
Depreciation and amortization expense	1,031	1,078	2,051	2,206
Other segment expenses	1,964	2,018	3,890	4,088
Total Operating Expenses	6,637	6,800	13,259	13,777
Operating Income	638	500	1,302	899
Operating Segments | Business | Wireless equipment
Segment Reporting Information [Line Items]
Operating revenues	886	855	1,800	1,700
Operating Segments | Business | Service revenues and other
Segment Reporting Information [Line Items]
Operating revenues	$ 6,400	$ 6,400	$ 12,800	$ 13,000