Segment Information (Segment Financial Information) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended				6 Months Ended				3 Months Ended			6 Months Ended		3 Months Ended			6 Months Ended		3 Months Ended				6 Months Ended				3 Months Ended	6 Months Ended		0 Months Ended			3 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended		0 Months Ended	3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended				3 Months Ended				6 Months Ended				0 Months Ended		3 Months Ended		0 Months Ended		3 Months Ended		0 Months Ended		3 Months Ended		0 Months Ended		3 Months Ended
	Sep. 30, 2014 segments	Sep. 30, 2014 Successor [Member]		Sep. 30, 2013 Successor [Member]		Sep. 30, 2014 Successor [Member]		Sep. 30, 2013 Successor [Member]		Sep. 30, 2014 Successor [Member] Wireless [Member]		Sep. 30, 2013 Successor [Member] Wireless [Member]	Sep. 30, 2014 Successor [Member] Wireless [Member]	Sep. 30, 2013 Successor [Member] Wireless [Member]	Sep. 30, 2014 Successor [Member] Wireline [Member]		Sep. 30, 2013 Successor [Member] Wireline [Member]	Sep. 30, 2014 Successor [Member] Wireline [Member]	Sep. 30, 2013 Successor [Member] Wireline [Member]	Sep. 30, 2014 Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2013 Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2014 Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2013 Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2014 Successor [Member] Lease [Member] Wireless [Member]	Sep. 30, 2014 Successor [Member] Lease [Member] Wireless [Member]		Jul. 08, 2013 Predecessor [Member]	Jul. 10, 2013 Predecessor [Member]		Jul. 09, 2013 Predecessor [Member]	Jul. 10, 2013 Predecessor [Member]		Jul. 10, 2013 Predecessor [Member] Wireless [Member]	Jul. 10, 2013 Predecessor [Member] Wireless [Member]	Jul. 10, 2013 Predecessor [Member] Wireline [Member]	Jul. 10, 2013 Predecessor [Member] Wireline [Member]	Jul. 10, 2013 Predecessor [Member] Corporate, Other And Eliminations [Member]		Jul. 10, 2013 Predecessor [Member] Corporate, Other And Eliminations [Member]		Jul. 10, 2013 Predecessor [Member] Lease [Member]	Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Wireless [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Wireless [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Wireless [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Wireless [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Wireline [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Wireline [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Wireline [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Wireline [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2014 Intersegment Eliminations [Member] Successor [Member] Corporate, Other And Eliminations [Member]		Sep. 30, 2013 Intersegment Eliminations [Member] Successor [Member] Corporate, Other And Eliminations [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Wireless [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Wireless [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Wireline [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Wireline [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Corporate, Other And Eliminations [Member]		Jul. 10, 2013 Intersegment Eliminations [Member] Predecessor [Member] Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Number of Reportable Segments	2
Segment Reporting Information, Total Net Operating Revenues		$ 8,488		$ 7,749		$ 17,277		$ 7,749		$ 7,929		$ 7,159	$ 16,122	$ 7,159	$ 555		$ 586	$ 1,148	$ 586	$ 4		$ 4		$ 7		$ 4						$ 932			$ 9,809		$ 858	$ 9,036	$ 74	$ 769	$ 0		$ 4
Revenues		8,488		7,749		17,277		7,749		7,929		7,159	16,122	7,159	708		777	1,454	777	(149)	[1]	(187)	[1]	(299)	[1]	(187)	[1]					932			9,809		858	9,036	98	1,008	(24)	[1]	(235)	[1]		0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	153	[2]	191	[2]	306	[2]	191	[2]	(153)	[2]	(191)	[2]	(306)	[2]	(191)	[2]	0	[2]	0	[2]	0	[2]	0	[2]	24	[2]	239	[2]	(24)	[2]	(239)	[2]
Segment Operating Expenses		(7,102)		(6,501)		(14,064)		(6,523)		(6,559)		(6,034)	(12,959)	(6,034)	(681)		(660)	(1,392)	(660)	138		193		287		171						(837)			(8,290)		(777)	(7,661)	(83)	(864)	23		235
Segment Reporting Information Operating Income or Loss		1,386		1,248		3,213		1,226		1,370		1,125	3,163	1,125	27		117	62	117	(11)		6		(12)		(16)						95			1,519		81	1,375	15	144	(1)		0
Depreciation		898		942		1,766		942																								113			1,676
Amortization		(396)		(461)		(809)		(461)																								(8)			(77)
Other, net		(284)	[3]	(203)	[3]	(311)	[3]	(203)	[3]																							(14)	[3]		(680)	[3]
Operating Income (Loss)		(192)		(358)		327		(380)																								(40)			(914)
Interest Expense		(510)		(416)		(1,022)		(416)																								(275)			(703)
Equity in losses of unconsolidated investments, net		0		0		0		0																							(23)	(23)		(280)	(280)
Gain on previously-held equity interests		0		0		0		0																								2,926			2,926
Income loss from equity method investments, net																																2,903			2,646
Other income (expense), net		8		165		9		12																								2			19
Loss (income) before income taxes		(694)		(609)		(686)		(784)																								2,590			1,048
Capital Expenditures						2,389		1,878					2,109	1,743				124	73					156		62									1,759			1,570		110			79
Severance and exit costs		284		103		311		103																								(5)			627
Business Combination, Acquisition Related Costs				100				100																								19			53
Severance Costs		263				269	[4]			228	[4]		233		35	[4]		36														32
Restructuring Charges						$ (311)																						$ (10)	$ (13)	[5]															$ (37)

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

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

[3] Other, net for the Successor three and six-month periods ended September 30, 2014 consists of $284 million and $311 million, respectively, of severance and exit costs. Other, net for both the Successor three and six-month periods ended September 30, 2013 consists of $103 million of severance and exit costs and $100 million of business combination fees paid to unrelated parties necessary for the transactions with SoftBank and Clearwire (included in our corporate segment and classified in our consolidated statements of comprehensive income (loss) as selling, general and administrative expenses). Other, net for the 101-day period ended July 10, 2013 consists of severance and exit costs of $627 million and $53 million of business combination fees paid to unrelated parties in connection with the transactions with SoftBank and Clearwire (included in our corporate segment and classified in our consolidated statements of comprehensive income (loss) as selling, general and administrative expenses). Other, net for the 10-day period ended July 10, 2013 consists of $32 million of severance costs primarily associated with the Clearwire Acquisition and $19 million of business combination fees paid to unrelated parties in connection with the transactions with SoftBank and Clearwire, partially offset by $37 million related to changes in estimates for lease exit costs previously recognized.

[4] For the Successor three and six-month periods ended September 30, 2014, we recognized costs of $263 million ($228 million Wireless, $35 million Wireline) and $269 million ($233 million Wireless, $36 million Wireline), respectively.

[5] For the Successor three and six-month periods ended September 30, 2014, we recognized costs of $10 million and $13 million ( Wireless only).