Segments (Segment Financial Information) (Details) $ in Millions		3 Months Ended				9 Months Ended
		Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)		Dec. 31, 2015 USD ($) segments	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments | segments						2
Segment Reporting Information, Total Net Operating Revenues		$ 8,107		$ 8,973		$ 24,109	$ 26,250
Revenues		8,107		8,973		24,109	26,250
Segment Operating Expenses		(6,209)		(7,929)		(18,121)	(21,993)
Segment Reporting Information Operating Income or Loss		1,898		1,044		5,988	4,257
Depreciation		1,549		940		4,202	2,706
Amortization		(316)		(380)		(994)	(1,189)
Impairments		0		(2,133)	[1]	0	(2,133)	[1]
Other Operating Expenses Net	[2]	230		131		490	442
Operating Income		(197)		(2,540)		302	(2,213)
Interest Expense		(546)		(506)		(1,630)	(1,528)
Other income, net		4		10		13	19
Loss (income) before income taxes		(739)		(3,036)		(1,315)	(3,722)
Payments to Acquire Property, Plant and Equipment Inclusive of Equipment on Lease						5,682	3,957
Severance and exit costs		209		22		247	333
Restructuring Charges						(227)
Pension Expense				(59)			(59)
Loss Contingency Accrual, Provision				(91)			(91)
Loss on Disposition of Property Plant Equipment						(228)	0
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)				1,900
Wireless [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues		7,670		8,433		22,726	24,555
Revenues		7,670		8,433		22,726	24,555
Segment Operating Expenses		(5,804)		(7,399)		(16,807)	(20,358)
Segment Reporting Information Operating Income or Loss		1,866		1,034		5,919	4,197
Payments to Acquire Property, Plant and Equipment Inclusive of Equipment on Lease						5,236	3,485
Loss on Disposition of Property Plant Equipment						(85)
Wireline [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues		434		536		1,372	1,684
Revenues		581		692		1,820	2,146
Segment Operating Expenses		(548)		(681)		(1,749)	(2,073)
Segment Reporting Information Operating Income or Loss		33		11		71	73
Payments to Acquire Property, Plant and Equipment Inclusive of Equipment on Lease						205	205
Impaired Assets to be Disposed of by Method Other than Sale, Amount of Impairment Loss				233
Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues		3		4		11	11
Revenues	[3]	(144)		(152)		(437)	(451)
Segment Operating Expenses		143		151		435	438
Segment Reporting Information Operating Income or Loss		(1)		(1)		(2)	(13)
Payments to Acquire Property, Plant and Equipment Inclusive of Equipment on Lease						241	267
Lease and severance [Member]
Segment Reporting Information [Line Items]
Severance and exit costs		209				247
Restructuring Charges				(22)			(333)
Lease [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	[4]					(30)
Lease [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	[5]	(32)				(50)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	[6]	0		0		0	0
Intersegment Eliminations [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Revenues		0		0		0	0
Intersegment Eliminations [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Revenues		147		156		448	462
Intersegment Eliminations [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues		(147)		(156)		(448)	(462)
Trademarks [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)				1,900
Other Operating Income (Expense) [Member]
Segment Reporting Information [Line Items]
Loss on Disposition of Property Plant Equipment		(78)				(163)
Other Operating Income (Expense) [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Restructuring Reserve, Accrual Adjustment				$ 41		20	$ 41
New York sales taxes on receipts from sale of wireless services [Member]
Segment Reporting Information [Line Items]
Loss Contingency Accrual, Provision		$ (21)	$ (178)			$ (180)

[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.

[2] Other, net for the three and nine-month periods ended December 31, 2015 consists of $209 million and $247 million, respectively, of severance and exit costs and $21 million and $178 million, respectively, of accruals for ongoing legal matters. In addition, the nine-month period ended December 31, 2015 includes an $85 million loss on disposal of property, plant and equipment related to cell site construction costs that are no longer recoverable as a result of changes in the Company's network plans and a $20 million release of liability reserves associated with the May 2013 U.S. Cellular asset acquisition. Other, net for the three and nine-month periods ended December 31, 2014 consists of $22 million and $333 million, respectively, of severance and exit costs

[3] Revenues eliminated in consolidation consist primarily of wireline services provided to the Wireless segment for resale to or use by wireless subscribers.

[4] In addition to the $20 million income (Wireless only) related to U.S. Cellular, we recognized costs of $32 million (Wireless only), and $50 million (Wireless only) for the three and nine-month periods ended December 31, 2015, respectively, included in "Severance and Exit Costs" on the consolidated statements of comprehensive loss.

[5] For the three and nine-month periods ended December 31, 2015, we recognized costs of $1 million (Wireless only), and $3 million (Wireless only), respectively, included in "Severance and Exit Costs" on the consolidated statements of comprehensive loss.

[6] Inter-segment revenues consist primarily of wireline services provided to the Wireless segment for resale to, or use by, wireless subscribers.