Segment Information (Summary Of Operating Revenues And Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenue	$ 45,739	$ 39,668	$ 122,763	$ 118,870
Operations and Support Expenses	30,304	27,819	82,289	81,865
EBITDA	15,435	11,849	40,474	37,005
Depreciation and Amortization	8,166	6,042	20,538	18,316
Operating Income (Loss)	7,269	5,807	19,936	18,689
Equity in Net Income (Loss) of Affiliates	(64)	11	(71)	(148)
Segment Contribution	6,207	4,974	19,128	16,422
Corporate [Member]
Segment Reporting Information [Line Items]
Revenue	308		961
Operating Segments [Member] | Communications [Member]
Segment Reporting Information [Line Items]
Revenue	36,230	37,115	107,173	111,268
Operations and Support Expenses	23,440	24,468	68,727	72,622
EBITDA	12,790	12,647	38,446	38,646
Depreciation and Amortization	4,607	4,576	13,820	13,825
Operating Income (Loss)	8,183	8,071	24,626	24,821
Equity in Net Income (Loss) of Affiliates	(1)	0	(3)	0
Segment Contribution	8,182	8,071	24,623	24,821
Operating Segments [Member] | Mobility [Member]
Segment Reporting Information [Line Items]
Revenue	17,938	17,370	52,575	51,922
Operations and Support Expenses	10,255	10,029	30,020	30,005
EBITDA	7,683	7,341	22,555	21,917
Depreciation and Amortization	2,079	2,008	6,287	5,988
Operating Income (Loss)	5,604	5,333	16,268	15,929
Equity in Net Income (Loss) of Affiliates	(1)	0	(1)	0
Segment Contribution	5,603	5,333	16,267	15,929
Operating Segments [Member] | Entertainment Group [Member]
Segment Reporting Information [Line Items]
Revenue	11,589	12,467	34,498	37,435
Operations and Support Expenses	9,155	9,804	26,623	28,711
EBITDA	2,434	2,663	7,875	8,724
Depreciation and Amortization	1,331	1,379	3,986	4,254
Operating Income (Loss)	1,103	1,284	3,889	4,470
Equity in Net Income (Loss) of Affiliates	1	(1)	(1)	0
Segment Contribution	1,104	1,283	3,888	4,470
Operating Segments [Member] | Business Wireline [Member]
Segment Reporting Information [Line Items]
Revenue	6,703	7,278	20,100	21,911
Operations and Support Expenses	4,030	4,635	12,084	13,906
EBITDA	2,673	2,643	8,016	8,005
Depreciation and Amortization	1,197	1,189	3,547	3,583
Operating Income (Loss)	1,476	1,454	4,469	4,422
Equity in Net Income (Loss) of Affiliates	(1)	1	(1)	0
Segment Contribution	1,475	1,455	4,468	4,422
Operating Segments [Member] | WarnerMedia [Member]
Segment Reporting Information [Line Items]
Revenue	8,204	107	9,709	323
Operations and Support Expenses	5,503	98	6,496	276
EBITDA	2,701	9	3,213	47
Depreciation and Amortization	134	1	166	3
Operating Income (Loss)	2,567	8	3,047	44
Equity in Net Income (Loss) of Affiliates	(39)	(6)	(55)	(23)
Segment Contribution	2,528	2	2,992	21
Operating Segments [Member] | Turner [Member]
Segment Reporting Information [Line Items]
Revenue	2,988	107	3,767	323
Operations and Support Expenses	1,487	97	1,933	273
EBITDA	1,501	10	1,834	50
Depreciation and Amortization	59	1	71	3
Operating Income (Loss)	1,442	9	1,763	47
Equity in Net Income (Loss) of Affiliates	7	13	39	32
Segment Contribution	1,449	22	1,802	79
Operating Segments [Member] | Home Box Office [Member]
Segment Reporting Information [Line Items]
Revenue	1,644	0	1,925	0
Operations and Support Expenses	991	0	1,162	0
EBITDA	653	0	763	0
Depreciation and Amortization	25	0	30	0
Operating Income (Loss)	628	0	733	0
Equity in Net Income (Loss) of Affiliates	2	0	1	0
Segment Contribution	630	0	734	0
Operating Segments [Member] | Warner Bros. [Member]
Segment Reporting Information [Line Items]
Revenue	3,720	0	4,227	0
Operations and Support Expenses	3,104	0	3,507	0
EBITDA	616	0	720	0
Depreciation and Amortization	40	0	54	0
Operating Income (Loss)	576	0	666	0
Equity in Net Income (Loss) of Affiliates	(23)	0	(24)	0
Segment Contribution	553	0	642	0
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Revenue	(148)	0	(210)	0
Operations and Support Expenses	(79)	1	(106)	3
EBITDA	(69)	(1)	(104)	(3)
Depreciation and Amortization	10	0	11	0
Operating Income (Loss)	(79)	(1)	(115)	(3)
Equity in Net Income (Loss) of Affiliates	(25)	(19)	(71)	(55)
Segment Contribution	(104)	(20)	(186)	(58)
Operating Segments [Member] | Latin America [Member]
Segment Reporting Information [Line Items]
Revenue	1,833	2,099	5,809	6,054
Operations and Support Expenses	1,746	1,937	5,353	5,468
EBITDA	87	162	456	586
Depreciation and Amortization	297	304	942	905
Operating Income (Loss)	(210)	(142)	(486)	(319)
Equity in Net Income (Loss) of Affiliates	9	17	24	62
Segment Contribution	(201)	(125)	(462)	(257)
Operating Segments [Member] | Vrio [Member]
Segment Reporting Information [Line Items]
Revenue	1,102	1,363	3,710	4,065
Operations and Support Expenses	877	1,075	2,894	3,123
EBITDA	225	288	816	942
Depreciation and Amortization	168	206	559	642
Operating Income (Loss)	57	82	257	300
Equity in Net Income (Loss) of Affiliates	9	17	24	62
Segment Contribution	66	99	281	362
Operating Segments [Member] | Mexico [Member]
Segment Reporting Information [Line Items]
Revenue	731	736	2,099	1,989
Operations and Support Expenses	869	862	2,459	2,345
EBITDA	(138)	(126)	(360)	(356)
Depreciation and Amortization	129	98	383	263
Operating Income (Loss)	(267)	(224)	(743)	(619)
Equity in Net Income (Loss) of Affiliates	0	0	0	0
Segment Contribution	(267)	(224)	(743)	(619)
Operating Segments [Member] | Xandr [Member]
Segment Reporting Information [Line Items]
Revenue	445	333	1,174	992
Operations and Support Expenses	109	39	218	118
EBITDA	336	294	956	874
Depreciation and Amortization	3	0	4	1
Operating Income (Loss)	333	294	952	873
Equity in Net Income (Loss) of Affiliates	0	0	0	0
Segment Contribution	333	294	952	873
Operating Segments [Member] | Segment Total [Member]
Segment Reporting Information [Line Items]
Revenue	46,712	39,654	123,865	118,637
Operations and Support Expenses	30,798	26,542	80,794	78,484
EBITDA	15,914	13,112	43,071	40,153
Depreciation and Amortization	5,041	4,881	14,932	14,734
Operating Income (Loss)	10,873	8,231	28,139	25,419
Equity in Net Income (Loss) of Affiliates	(31)	11	(34)	39
Segment Contribution	10,842	8,242	28,105	25,458
Consolidation Non-Segment [Member] | Corporate [Member]
Segment Reporting Information [Line Items]
Revenue	308	382	961	1,182
Operations and Support Expenses	(18)	801	1,378	2,440
EBITDA	326	(419)	(417)	(1,258)
Depreciation and Amortization	797	24	938	73
Operating Income (Loss)	(471)	(443)	(1,355)	(1,331)
Consolidation Non-Segment [Member] | Acquisition-related items [Member]
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
Operations and Support Expenses	362	134	750	622
EBITDA	(362)	(134)	(750)	(622)
Depreciation and Amortization	2,329	1,136	4,669	3,508
Operating Income (Loss)	(2,691)	(1,270)	(5,419)	(4,130)
Consolidation Non-Segment [Member] | Certain Significant Items [Member]
Segment Reporting Information [Line Items]
Revenue	0	(89)	0	(89)
Operations and Support Expenses	75	325	407	302
EBITDA	(75)	(414)	(407)	(391)
Depreciation and Amortization	0	1	0	1
Operating Income (Loss)	(75)	(415)	(407)	(392)
Eliminations and consolidations [Member]
Segment Reporting Information [Line Items]
Revenue	(1,281)	(279)	(2,063)	(860)
Operations and Support Expenses	(913)	17	(1,040)	17
EBITDA	(368)	(296)	(1,023)	(877)
Depreciation and Amortization	(1)	0	(1)	0
Operating Income (Loss)	$ (367)	$ (296)	$ (1,022)	$ (877)