Segments (Segment Financial Information) (Details) (USD $)	12 Months Ended		3 Months Ended													6 Months Ended				12 Months Ended		15 Months Ended	0 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2015 segments		Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014		Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013		Dec. 31, 2012		Dec. 31, 2013		Jul. 10, 2013		Dec. 31, 2013		Mar. 31, 2014	Jul. 10, 2013	Jul. 09, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of reportable segments	2
Successor [Member]
Segment Reporting Information [Line Items]
Net operating revenues	34,532,000,000						$ 8,875,000,000					$ 0		$ 0				$ 16,891,000,000		$ 16,891,000,000
Inter-segment revenues	34,532,000,000		8,292,000,000	8,973,000,000	8,488,000,000	8,789,000,000	8,875,000,000		9,142,000,000	7,749,000,000	0	0		0						16,891,000,000
Total segment operating expenses	(28,532,000,000)						(7,031,000,000)					(14,000,000)		(33,000,000)						(14,525,000,000)
Segment earnings	6,000,000,000						1,844,000,000					(14,000,000)		(33,000,000)						2,366,000,000
Depreciation	3,797,000,000						868,000,000					0		0						2,026,000,000
Amortization	(1,552,000,000)						(429,000,000)					0		0						(908,000,000)
Impairments	(2,133,000,000)	[1]					(75,000,000)	[1]				0		0						0
Other, net	(413,000,000)	[2]					(52,000,000)	[2]												(402,000,000)	[2]
Operating (loss) income	(1,895,000,000)		318,000,000	(2,540,000,000)	(192,000,000)	519,000,000	420,000,000		(576,000,000)	(358,000,000)	(22,000,000)	(14,000,000)		(33,000,000)						(970,000,000)
Interest expense	(2,051,000,000)						(516,000,000)					0		0						(918,000,000)
Equity in losses of unconsolidated investments, net	0						0					0		0						0
Gain on previously-held equity interests	0						0					0		0						0
Other income (expense), net	27,000,000						1,000,000					6,000,000		10,000,000						73,000,000
Income (loss) before income taxes	(3,919,000,000)						(95,000,000)					(8,000,000)		(23,000,000)						(1,815,000,000)
Capital expenditures - network and other	5,422,000,000						1,488,000,000					0		0						3,847,000,000		1,488,000,000
Capital expenditures - network and other, inclusive of equipment on lease	6,004,000,000
Assets	83,030,000,000		83,030,000,000				84,689,000,000		86,095,000,000			3,122,000,000		3,115,000,000		86,095,000,000				86,095,000,000		84,689,000,000			3,115,000,000
Severance, exit costs and asset impairments	(304,000,000)						(52,000,000)
Legal fees	(91,000,000)
Pension expense	59,000,000
Severance and exit costs	304,000,000						52,000,000					0		0						309,000,000
Business combination, acquisition related costs																				(100,000,000)
Other nonrecurring (income) expense																7,000,000
Restructuring charges	(263,000,000)						(56,000,000)									(328,000,000)
Other, net	(109,000,000)						0					0		0						0
Successor [Member] | Corporate Segment [Member]
Segment Reporting Information [Line Items]
Business combination, acquisition related costs																				(75,000,000)
Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Net operating revenues	32,327,000,000						8,254,000,000					0		0						15,642,000,000
Inter-segment revenues	32,327,000,000						8,254,000,000													15,642,000,000
Total segment operating expenses	(26,433,000,000)						(6,417,000,000)					0		0						(13,464,000,000)
Segment earnings	5,894,000,000						1,837,000,000					0		0						2,178,000,000
Capital expenditures - network and other	5,442,000,000																			3,535,000,000		1,343,000,000
Assets	75,581,000,000		75,581,000,000				75,051,000,000		75,128,000,000			0		0		75,128,000,000				75,128,000,000		75,051,000,000			0
Restructuring reserve, accrual adjustment	41,000,000
Business combination, acquisition related costs																				(25,000,000)
Successor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Net operating revenues	2,191,000,000						617,000,000					0		0						1,240,000,000
Inter-segment revenues	2,814,000,000						770,000,000											1,636,000,000
Total segment operating expenses	(2,701,000,000)						(758,000,000)					0		0						(1,414,000,000)
Segment earnings	113,000,000						12,000,000					0		0						222,000,000
Capital expenditures - network and other	275,000,000																			153,000,000		79,000,000
Assets	1,261,000,000		1,261,000,000				1,499,000,000		1,548,000,000			0		0		1,548,000,000				1,548,000,000		1,499,000,000			0
Impairment loss				233,000,000
Successor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Net operating revenues	14,000,000						4,000,000					0		0						9,000,000
Inter-segment revenues	(609,000,000)	[3]					(149,000,000)	[3]										(387,000,000)	[3]
Total segment operating expenses	602,000,000						144,000,000					(14,000,000)		(33,000,000)						353,000,000
Segment earnings	(7,000,000)						(5,000,000)					(14,000,000)		(33,000,000)						(34,000,000)
Capital expenditures - network and other	287,000,000																			159,000,000		66,000,000
Assets	6,188,000,000		6,188,000,000				8,139,000,000		9,419,000,000			3,122,000,000		3,115,000,000		9,419,000,000				9,419,000,000		8,139,000,000			3,115,000,000
Successor [Member] | Lease [Member]
Segment Reporting Information [Line Items]
Restructuring charges	28,000,000	[4]					(11,000,000)	[5]								(56,000,000)	[6]
Successor [Member] | Lease [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Restructuring charges	(12,000,000)															(54,000,000)
Successor [Member] | Lease [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Restructuring charges	(1,000,000)															(2,000,000)
Predecessor [Member]
Segment Reporting Information [Line Items]
Net operating revenues												8,793,000,000						18,602,000,000							35,366,000,000
Inter-segment revenues										8,877,000,000		8,793,000,000						18,602,000,000					932,000,000		35,345,000,000
Total segment operating expenses												(7,269,000,000)						(15,559,000,000)							(30,563,000,000)
Segment earnings												1,524,000,000						3,043,000,000							4,803,000,000
Depreciation												1,422,000,000						3,098,000,000							6,240,000,000
Amortization												(70,000,000)						(147,000,000)							(303,000,000)
Business combination and hurricane-related charges																									(64,000,000)	[7]
Impairments												0						0							(102,000,000)	[1]
Other, net												(3,000,000)	[2]					(683,000,000)	[2]						86,000,000	[2]
Operating (loss) income										874,000,000		29,000,000						(885,000,000)					(40,000,000)		(1,820,000,000)
Interest expense												(432,000,000)						(1,135,000,000)							(1,428,000,000)
Equity in losses of unconsolidated investments, net												(202,000,000)						(482,000,000)						(482,000,000)	(1,114,000,000)
Gain on previously-held equity interests												0						2,926,000,000							0
Income loss from equity method investments, net												(202,000,000)						2,444,000,000
Other income (expense), net												0						19,000,000							190,000,000
Income (loss) before income taxes												(605,000,000)						443,000,000							(4,172,000,000)
Capital expenditures - network and other												1,381,000,000						3,140,000,000							4,261,000,000
Assets														51,570,000,000											51,570,000,000
Severance, exit costs and asset impairments												(25,000,000)
Severance and exit costs												25,000,000						652,000,000							196,000,000
Business combination, acquisition related costs																		(53,000,000)							(19,000,000)
Other nonrecurring (income) expense																									(45,000,000)
Restructuring charges																		(687,000,000)
Other, net												22,000,000						22,000,000							282,000,000
Payment received for incremental costs or obligations incurred by the Company for Spectrum Hosting																									236,000,000
Gain Loss from asset dispositions and exchanges																									29,000,000
Net benefit resulting from favorable developments relating to access cost disputes associated with prior periods																									17,000,000
Cost of services and products, nonrecurring																									20,000,000
Predecessor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Net operating revenues												8,089,000,000						17,125,000,000							32,355,000,000
Inter-segment revenues												8,089,000,000						17,125,000,000							32,355,000,000
Total segment operating expenses												(6,694,000,000)						(14,355,000,000)							(28,208,000,000)
Segment earnings												1,395,000,000						2,770,000,000							4,147,000,000
Capital expenditures - network and other												1,270,000,000						2,840,000,000							3,753,000,000
Assets														38,297,000,000											38,297,000,000
Other nonrecurring (income) expense																									(4,000,000)
Contra Revenue																									21,000,000
Cost of services and products, nonrecurring																									17,000,000
Predecessor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Net operating revenues												702,000,000						1,471,000,000							2,999,000,000
Inter-segment revenues												893,000,000						1,901,000,000							3,881,000,000
Total segment operating expenses												(765,000,000)						(1,629,000,000)							(3,232,000,000)
Segment earnings												128,000,000						272,000,000							649,000,000
Capital expenditures - network and other												64,000,000						174,000,000							240,000,000
Assets														2,195,000,000											2,195,000,000
Cost of services and products, nonrecurring																									3,000,000
Predecessor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Net operating revenues												2,000,000						6,000,000							12,000,000
Inter-segment revenues												(189,000,000)	[3]					(424,000,000)	[3]						(870,000,000)	[3]
Total segment operating expenses												190,000,000						425,000,000							877,000,000
Segment earnings												1,000,000						1,000,000							7,000,000
Capital expenditures - network and other												47,000,000						126,000,000							268,000,000
Assets														11,078,000,000											11,078,000,000
Predecessor [Member] | Lease [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Restructuring charges												(8,000,000)	[8]					(478,000,000)	[8]						(196,000,000)
Intersegment Eliminations [Member] | Successor [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	0	[9]					0	[9]				0	[9]	0	[9]					0	[9]
Intersegment Eliminations [Member] | Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	0	[9]					0	[9]				0	[9]	0	[9]					0	[9]
Intersegment Eliminations [Member] | Successor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	623,000,000	[9]					153,000,000	[9]				0	[9]	0	[9]					396,000,000	[9]
Intersegment Eliminations [Member] | Successor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues	(623,000,000)	[9]					(153,000,000)	[9]				0	[9]	0	[9]					(396,000,000)	[9]
Intersegment Eliminations [Member] | Predecessor [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues												0	[9]					0	[9]						0	[9]
Intersegment Eliminations [Member] | Predecessor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues												0	[9]					0	[9]						0	[9]
Intersegment Eliminations [Member] | Predecessor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues												191,000,000	[9]					430,000,000	[9]						882,000,000	[9]
Intersegment Eliminations [Member] | Predecessor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Inter-segment revenues												(191,000,000)	[9]					(430,000,000)	[9]						(882,000,000)	[9]
Equity in losses of unconsolidated investments, net																									(1,114,000,000)
Trademarks [Member] | Successor [Member]
Segment Reporting Information [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)	1,900,000,000	[10]
Trademarks [Member] | Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)				$ 1,900,000,000

[1] (2)Impairments for the Successor year ended March 31, 2015 consist of a $1.9 billion trade name impairment related to the Wireless segment and a $233 million impairment related to Wireline long-lived assets. Impairments for the Successor three-month transition period ended March 31, 2014 consist of network equipment assets no longer necessary for management's strategic plans. Impairments for the Predecessor year ended December 31, 2012 primarily consist of capitalized assets associated with the termination of the spectrum hosting arrangement with LightSquared.

[2] (3)Other, net for the Successor year ended March 31, 2015 consists of $304 million of severance and exit costs, combined with $91 million for legal reserves related to various pending legal suits and proceedings and $59 million for a partial pension settlement, partially offset by a $41 million release of liability reserves associated with the May 2013 U.S. Cellular asset acquisition. Other, net for the Successor three-month transition period ended March 31, 2014 consists of $52 million of severance and exit costs. Other, net for the Successor year ended December 31, 2013 consists of $309 million of severance and exit costs and $100 million of business combination fees paid to unrelated parties in connection with the transactions with SoftBank and Clearwire ($75 million included in our corporate segment and $25 million included in our wireless segment and classified as selling, general and administrative expenses), partially offset by $7 million of insurance reimbursement towards 2012 hurricane-related charges (included in our wireless segment and classified as a contra-expense in cost of services expense). Other, net for the Predecessor 191-day period ended July 10, 2013 and unaudited three-month period ended March 31, 2013 consists of $652 million and $25 million, respectively, of severance and exit costs, partially offset by $22 million of favorable developments in connection with an E911 regulatory tax-related contingency. Other, net for the Predecessor 191-day period ended July 10, 2013 also includes $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 as selling, general and administrative expenses). Other, net for the Predecessor year ended December 31, 2012 consists of net operating income of $236 million associated with the termination of the spectrum hosting arrangement with LightSquared, a gain of $29 million on spectrum swap transactions, and a benefit of $17 million resulting from favorable developments relating to access cost disputes associated with prior periods, partially offset by $196 million of lease exit costs.

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

[4] (1)In addition to the $41 million gain (Wireless only) related to U.S. Cellular recognized, we recognized costs of $13 million ($12 million Wireless and $1 million Wireline) for the year ended March 31, 2015.

[5] (4)For the three-month transition period ended March 31, 2014, we recognized costs of $11 million (solely attributable to Wireless).

[6] (8)For the year ended December 31, 2013, we recognized costs of $56 million ($54 million Wireless, $2 million Wireline).

[7] (4)Includes $45 million of hurricane-related charges for the Predecessor year ended December 31, 2012, which are classified in our consolidated statements of operations as follows: $21 million as contra-revenue in net operating revenues of Wireless, $20 million as cost of services ($17 million Wireless; $3 million Wireline), and $4 million as selling, general and administrative expenses in our Wireless segment. Also includes $19 million of business combination charges for fees paid to unrelated parties necessary for the proposed transactions with SoftBank and Clearwire, which is included in our corporate segment and classified as selling, general and administrative expenses.

[8] (11)For the 191-day period ended July 10, 2013, we recognized net costs of $478 million (solely attributable to our Wireless segment). For the unaudited three-month period ended March 31, 2013, we recognized net costs of $8 million (solely attributable to our Wireless segment).

[9] (1)Inter-segment revenues consist primarily of wireline services provided to the Wireless segment for resale to or use by wireless subscribers.

[10] Net reduction to trademarks for the year ended March 31, 2015 of approximately $1.9 billion was related to the impairment of the Sprint trade name. See discussion below.