Segment Information (Summary Of Operating Revenues And Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 44,827	$ 38,038
Operations and Support Expenses	30,388	25,843
EBITDA	14,439	12,195
Depreciation and Amortization	7,206	5,994
Operating Income (Loss)	7,233	6,201
Equity in Net Income (Loss) of Affiliates	(7)	9
Segment Contribution	5,371	6,141
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	45,916	38,007
Operations and Support Expenses	30,492	24,865
EBITDA	15,424	13,142
Depreciation and Amortization	5,049	4,909
Operating Income (Loss)	10,375	8,233
Equity in Net Income (Loss) of Affiliates	67	8
Segment Contribution	10,442	8,241
Consolidations [Member]
Segment Reporting Information [Line Items]
Revenue	209	333
Operations and Support Expenses	513	735
EBITDA	(304)	(402)
Depreciation and Amortization	169	23
Operating Income (Loss)	(473)	(425)
Consolidations [Member] | Acquisition-related items [Member]
Segment Reporting Information [Line Items]
Revenue	(42)	0
Operations and Support Expenses	73	67
EBITDA	(115)	(67)
Depreciation and Amortization	1,988	1,062
Operating Income (Loss)	(2,103)	(1,129)
Eliminations and consolidations [Member]
Segment Reporting Information [Line Items]
Revenue	(1,256)	(302)
Operations and Support Expenses	(938)	(4)
EBITDA	(318)	(298)
Depreciation and Amortization	0	0
Operating Income (Loss)	(318)	(298)
Certain Significant Items [Member]
Segment Reporting Information [Line Items]
Revenue	0	0
Operations and Support Expenses	248	180
EBITDA	(248)	(180)
Depreciation and Amortization	0	0
Operating Income (Loss)	(248)	(180)
Communications [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	35,393	35,533
Operations and Support Expenses	22,748	22,929
EBITDA	12,645	12,604
Depreciation and Amortization	4,593	4,575
Operating Income (Loss)	8,052	8,029
Equity in Net Income (Loss) of Affiliates	0	(2)
Segment Contribution	8,052	8,027
Communications [Member] | Mobility [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	17,567	17,355
Operations and Support Expenses	10,181	10,102
EBITDA	7,386	7,253
Depreciation and Amortization	2,035	2,095
Operating Income (Loss)	5,351	5,158
Equity in Net Income (Loss) of Affiliates	0	0
Segment Contribution	5,351	5,158
Communications [Member] | Entertainment Group [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	11,328	11,431
Operations and Support Expenses	8,527	8,811
EBITDA	2,801	2,620
Depreciation and Amortization	1,323	1,310
Operating Income (Loss)	1,478	1,310
Equity in Net Income (Loss) of Affiliates	0	(1)
Segment Contribution	1,478	1,309
Communications [Member] | Business Wireline [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	6,498	6,747
Operations and Support Expenses	4,040	4,016
EBITDA	2,458	2,731
Depreciation and Amortization	1,235	1,170
Operating Income (Loss)	1,223	1,561
Equity in Net Income (Loss) of Affiliates	0	(1)
Segment Contribution	1,223	1,560
WarnerMedia [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	8,379	112
Operations and Support Expenses	5,993	82
EBITDA	2,386	30
Depreciation and Amortization	143	1
Operating Income (Loss)	2,243	29
Equity in Net Income (Loss) of Affiliates	67	10
Segment Contribution	2,310	39
WarnerMedia [Member] | Turner [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	3,443	112
Operations and Support Expenses	2,136	74
EBITDA	1,307	38
Depreciation and Amortization	60	1
Operating Income (Loss)	1,247	37
Equity in Net Income (Loss) of Affiliates	25	27
Segment Contribution	1,272	64
WarnerMedia [Member] | Home Box Office [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	1,510	0
Operations and Support Expenses	921	0
EBITDA	589	0
Depreciation and Amortization	22	0
Operating Income (Loss)	567	0
Equity in Net Income (Loss) of Affiliates	15	0
Segment Contribution	582	0
WarnerMedia [Member] | Warner Bros. [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	3,518	0
Operations and Support Expenses	2,919	0
EBITDA	599	0
Depreciation and Amortization	52	0
Operating Income (Loss)	547	0
Equity in Net Income (Loss) of Affiliates	6	0
Segment Contribution	553	0
WarnerMedia [Member] | Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	(92)	0
Operations and Support Expenses	17	8
EBITDA	(109)	(8)
Depreciation and Amortization	9	0
Operating Income (Loss)	(118)	(8)
Equity in Net Income (Loss) of Affiliates	21	(17)
Segment Contribution	(97)	(25)
Latin America [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	1,718	2,025
Operations and Support Expenses	1,591	1,804
EBITDA	127	221
Depreciation and Amortization	300	332
Operating Income (Loss)	(173)	(111)
Equity in Net Income (Loss) of Affiliates	0	0
Segment Contribution	(173)	(111)
Latin America [Member] | Vrio [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	1,067	1,354
Operations and Support Expenses	866	1,001
EBITDA	201	353
Depreciation and Amortization	169	205
Operating Income (Loss)	32	148
Equity in Net Income (Loss) of Affiliates	0	0
Segment Contribution	32	148
Latin America [Member] | Mexico [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	651	671
Operations and Support Expenses	725	803
EBITDA	(74)	(132)
Depreciation and Amortization	131	127
Operating Income (Loss)	(205)	(259)
Equity in Net Income (Loss) of Affiliates	0	0
Segment Contribution	(205)	(259)
Xandr [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue	426	337
Operations and Support Expenses	160	50
EBITDA	266	287
Depreciation and Amortization	13	1
Operating Income (Loss)	253	286
Equity in Net Income (Loss) of Affiliates	0	0
Segment Contribution	253	286
Corporate [Member]
Segment Reporting Information [Line Items]
Revenue	$ 167	$ 333