Segment Information (Intersegment Details) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenues [Abstract]
Total revenues	$ (45,739)	$ (39,668)	$ (122,763)	$ (118,870)
Total Assets	534,870		534,870		$ 444,097
Investments in Equity Method Investees	6,128		6,128		$ 1,560
Capital Expenditures			17,099
Corporate and other [Member]
Revenues [Abstract]
Total Assets	(106,719)		(106,719)
Investments in Equity Method Investees	19		19
Capital Expenditures			187
Total Intersegment Revenues [Member]
Revenues [Abstract]
Total revenues	850	33	1,061	99
Eliminations and consolidations [Member]
Revenues [Abstract]
Total revenues	1,281	279	2,063	860
Communications [Member] | Operating Segments [Member]
Revenues [Abstract]
Total revenues	(36,230)	(37,115)	(107,173)	(111,268)
Total Assets	487,833		487,833
Investments in Equity Method Investees	1		1
Capital Expenditures			16,024
Communications [Member] | Total Intersegment Revenues [Member]
Revenues [Abstract]
Total revenues	6	0	8	0
WarnerMedia [Member] | Operating Segments [Member]
Revenues [Abstract]
Total revenues	(8,204)	(107)	(9,709)	(323)
Total Assets	132,689		132,689
Investments in Equity Method Investees	5,395		5,395
Capital Expenditures			298
WarnerMedia [Member] | Total Intersegment Revenues [Member]
Revenues [Abstract]
Total revenues	844	33	1,053	99
Latin America [Member] | Operating Segments [Member]
Revenues [Abstract]
Total revenues	(1,833)	(2,099)	(5,809)	(6,054)
Total Assets	18,420		18,420
Investments in Equity Method Investees	713		713
Capital Expenditures			524
Latin America [Member] | Total Intersegment Revenues [Member]
Revenues [Abstract]
Total revenues	0	0	0	0
Xandr [Member] | Operating Segments [Member]
Revenues [Abstract]
Total revenues	(445)	(333)	(1,174)	(992)
Total Assets	2,647		2,647
Investments in Equity Method Investees	0		0
Capital Expenditures			66
Xandr [Member] | Total Intersegment Revenues [Member]
Revenues [Abstract]
Total revenues	0	0	0	0
Operating Segments [Member] | Eliminations and consolidations [Member]
Revenues [Abstract]
Total revenues	$ 431	$ 246	$ 1,002	$ 761