Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Increase (Decrease) in Accounts Payable	$ 309	$ 1,200
Sale Leaseback Transaction, Net Book Value	500		$ 1,200	$ 1,300
Depreciation	1,680	1,241
Loss on Disposition of Property Plant Equipment	120	0
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Increase (Decrease) in Accounts Payable	142	207
Increase (Decrease) in Inventories	500	808
Depreciation	$ 644	276
Wireline [Member]
Property, Plant and Equipment [Line Items]
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss		$ 233