Acquisitions, Dispositions And Other Adjustments (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions					1 Months Ended		3 Months Ended			6 Months Ended	9 Months Ended
	Jul. 24, 2015	Jun. 30, 2015	Apr. 30, 2015	Jan. 16, 2015	Jan. 31, 2015	Oct. 31, 2014	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Acquisition and Dispositions [Line Items]
Acquisition of business - anticipated or actual cash paid to seller											$ 30,694	$ 2,053
Revenue for Venuezuela using SICAD exchange rate							$ 39,091		$ 32,957		104,682	98,008
Operating profit for Venuezuela using SICAD exchange rate							$ 12,188		$ 10,146		$ 32,792	$ 31,387
DIRECTV [Member]
Acquisition and Dispositions [Line Items]
Long-term Debt, Fair Value	$ 20,500
DIRECTV [Member] | Acquisition [Member]
Acquisition and Dispositions [Line Items]
Acquisition of business - anticipated or actual acquisition period	Jul. 24, 2015
Acquisition of business - approximate acquisition value	$ 47,404
Acquisition of business - cash payment to acquire assets	$ 14,378
Acquisition of business - cash payment to acquire assets (in US dollars per share)	$ 28.50
Acquisition of business - noncash consideration	1.892 shares of AT&T stock per share of DIRECTV for 954,407,524 shares issued to DIRECTV shareholders for an approximate 16% stake in the combined company
Acquisition of business - value of noncash consideration given (in millions)	$ 32,727
Acquisition of business - value of noncash consideration (in US dollars per share)	$ 34.29
Acquisition of business - noncash consideration given number of shares	954,407,524
Acquisition of business - percentage ownership of combined company held by former shareholders of acquiree	16.00%
Acquisition of business - value of shared-based payment arrangements given (in millions)	$ 299
Impairment charge related to Venuzuelan change in exchange rate		$ 1,060
Revenue for Venuezuela using SICAD exchange rate										$ 500
Operating profit for Venuezuela using SICAD exchange rate										$ 180
FCC Auction 97 [Member] | Acquisition [Member] | Spectrum Licenses [Member]
Acquisition and Dispositions [Line Items]
Acquisition of assets - anticipated or actual acquisition date					Jan. 31, 2015
Acquisition of intangible assets through a group purchase - value/amount of assets acquired					$ 18,189
License Purchase Agreement Description					251 Advanced Wireless Service (AWS) spectrum
Payments To Acquire Intangible Assets						$ 921		$ 17,268
GSF Telecom Holdings [Member] | Acquisition [Member]
Acquisition and Dispositions [Line Items]
Acquisition of assets - anticipated or actual acquisition date				Jan. 16, 2015
Acquistion of business - allocaton to debt, net of cash received by seller				$ 700
Acquisition of business - anticipated or actual cash paid to seller				2,500
GSF Telecom Holdings [Member] | Acquisition [Member] | Property, Plant and Equipment [Member]
Acquisition and Dispositions [Line Items]
Acquisition of business - preliminary value/amount of assets acquired				712
GSF Telecom Holdings [Member] | Acquisition [Member] | Customer lists and relationships [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired				311
GSF Telecom Holdings [Member] | Acquisition [Member] | Goodwill [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired				1,124
GSF Telecom Holdings [Member] | Acquisition [Member] | Spectrum Licenses [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired				920
GSF Telecom Holdings [Member] | Acquisition [Member] | Trade Names [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired				$ 26
Nextel Mexico [Member] | Acquisition [Member]
Acquisition and Dispositions [Line Items]
Acquisition of business - anticipated or actual acquisition period			Apr. 30, 2015
Acquistion of business - allocaton to debt, net of cash received by seller			$ 427
Acquisition of business - anticipated or actual cash paid to seller			1,875
Nextel Mexico [Member] | Acquisition [Member] | Property, Plant and Equipment [Member]
Acquisition and Dispositions [Line Items]
Acquisition of business - preliminary value/amount of assets acquired			1,391
Nextel Mexico [Member] | Acquisition [Member] | Customer lists and relationships [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired			65
Nextel Mexico [Member] | Acquisition [Member] | Goodwill [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired			414
Nextel Mexico [Member] | Acquisition [Member] | Spectrum Licenses [Member]
Acquisition and Dispositions [Line Items]
Acquisition of intangible assets - value/amount of assets acquired			$ 376