Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2015	Dec. 31, 2014		Nov. 19, 2015
Property, Plant and Equipment [Line Items]
Increase (Decrease) in Accounts Payable				$ 763	$ 2,000
Sale Leaseback Transaction, Net Book Value							$ 1,300
Impairments	$ 0	$ 2,133	[1]	0	2,133	[1]
Depreciation	1,549	940		4,202	2,706
Loss on Disposition of Property Plant Equipment				228	0
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Increase (Decrease) in Accounts Payable				306	150
Increase (Decrease) in Inventories				2,600	700
Depreciation	535	54		1,200	56
Wireline [Member]
Property, Plant and Equipment [Line Items]
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss		233
Property, Plant, and Equipment, Fair Value Disclosure		$ 918			$ 918
Other Operating Income (Expense) [Member]
Property, Plant and Equipment [Line Items]
Loss on Disposition of Property Plant Equipment	$ 78			$ 163

[1] Impairments for the three and nine-month periods ended December 31, 2014 consist of a $1.9 billion Sprint trade name impairment related to the Wireless segment and a $233 million impairment related to Wireline long-lived assets.