Preparation Of Interim Financial Statements (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 55,094			$ 55,094			$ 57,936
Contract asset	2,817			2,817			2,472
Deferred income taxes	60,448			60,448			59,502
Noncontrolling interest	19,503			19,503			$ 17,713
Goodwill impairment	$ 73		$ 0	$ 2,515	$ 0
Diluted earnings per share attributable to Common Stock (in dollars per share)	$ 0.39		$ 0.50	$ 1.19	$ 1.57
Venezuela | Latin America | Vrio
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noncontrolling interest		$ (105)
Goodwill impairment		$ 2,212
Intangible Assets, Amortization Period | Latin America | Trade Names
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated economic useful life				15 years
Intangible Assets, Amortization Period | Communications | Orbital Slot Licenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated economic useful life				15 years
Amortization expense	$ 373			$ 1,138
Diluted earnings per share attributable to Common Stock (in dollars per share)	$ 0.04			$ 0.12
ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings						$ (293)
Allowance for doubtful accounts						395
Contract asset						(10)
Deferred income taxes						(105)
Noncontrolling interest						$ (7)