Guarantor Financial Information (CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS)) (Details) (USD $)	6 Months Ended	3 Months Ended											12 Months Ended			0 Months Ended	3 Months Ended	12 Months Ended
	Jul. 10, 2013	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	Mar. 31, 2015		Dec. 31, 2013	Jul. 10, 2013	Jul. 09, 2013	Dec. 31, 2012
Other (expense) income:
Income tax benefit (expense)	$ (1,600,000,000)
Successor [Member]
Condensed Income Statements, Captions [Line Items]
Service						7,876,000,000					0	0	29,542,000,000		15,094,000,000
Equipment						999,000,000					0	0	4,990,000,000		1,797,000,000
Revenues		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	34,532,000,000		16,891,000,000
Cost of services (exclusive of depreciation and amortization below)						2,622,000,000					0	0	9,660,000,000		5,174,000,000
Cost of products (exclusive of depreciation and amortization below)						2,038,000,000					0	0	9,309,000,000		4,603,000,000
Net operating expenses:
Selling, general and administrative						2,371,000,000					14,000,000	33,000,000	9,563,000,000		4,841,000,000
Severance, exit costs and asset impairments						52,000,000							304,000,000
Depreciation						868,000,000					0	0	3,797,000,000		2,026,000,000
Amortization						429,000,000					0	0	1,552,000,000		908,000,000
Total costs and expenses						8,455,000,000					14,000,000	33,000,000	36,427,000,000		17,861,000,000
Operating (loss) income		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)	(1,895,000,000)		(970,000,000)
Other (expense) income:
Interest and Other Income						4,000,000							12,000,000		35,000,000
Interest Expense						(516,000,000)					0	0	(2,051,000,000)		(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
(Losses) earnings of subsidiaries						0							0		0
Other nonoperating income (expense), excluding interest income						(3,000,000)							15,000,000		38,000,000
Nonoperating income (expense)						(515,000,000)					6,000,000	10,000,000	(2,024,000,000)		(845,000,000)
Income (loss) before income taxes						(95,000,000)					(8,000,000)	(23,000,000)	(3,919,000,000)		(1,815,000,000)
Income tax benefit (expense)						(56,000,000)					(1,000,000)	(4,000,000)	574,000,000		(45,000,000)
Net loss		(224,000,000)	(2,379,000,000)	(765,000,000)	23,000,000	(151,000,000)		(1,038,000,000)	(699,000,000)	(114,000,000)	(9,000,000)	(27,000,000)	(3,345,000,000)		(1,860,000,000)
Other comprehensive (loss) income						(145,000,000)					0	0	(365,000,000)		102,000,000
Comprehensive (loss)						(296,000,000)					(9,000,000)	(27,000,000)	(3,710,000,000)		(1,758,000,000)
Asset impairments						75,000,000	[1]				0	0	2,133,000,000	[1]	0
Severance and exit costs						52,000,000					0	0	304,000,000		309,000,000
Other income (expense), net						1,000,000					6,000,000	10,000,000	27,000,000		73,000,000
Other, net						0					0	0	109,000,000		0
Successor [Member] | Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Service						0							0		0
Equipment						0							0		0
Revenues						0							0		0
Cost of services (exclusive of depreciation and amortization below)						0							0		0
Cost of products (exclusive of depreciation and amortization below)						0							0		0
Net operating expenses:
Selling, general and administrative						0							0		0
Depreciation						0							0		0
Amortization						0							0		0
Total costs and expenses						0							1,000,000		0
Operating (loss) income						0							(1,000,000)		0
Other (expense) income:
Interest and Other Income						20,000,000							146,000,000		40,000,000
Interest Expense						(373,000,000)							(1,521,000,000)		(548,000,000)
Equity in losses of unconsolidated investments, net													0
Gain on previously-held equity interests													0
(Losses) earnings of subsidiaries						199,000,000							(1,970,000,000)		(1,320,000,000)
Other nonoperating income (expense), excluding interest income						0							1,000,000		(3,000,000)
Nonoperating income (expense)						(154,000,000)							(3,344,000,000)		(1,831,000,000)
Income (loss) before income taxes						(154,000,000)							(3,345,000,000)		(1,831,000,000)
Income tax benefit (expense)						0							0		0
Net loss						(154,000,000)							(3,345,000,000)		(1,831,000,000)
Other comprehensive (loss) income						(145,000,000)							(365,000,000)		102,000,000
Comprehensive (loss)						(299,000,000)							(3,710,000,000)		(1,729,000,000)
Asset impairments						0							0
Severance and exit costs						0							0		0
Other, net													1,000,000
Successor [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Service						7,876,000,000							29,542,000,000		15,094,000,000
Equipment						999,000,000							4,990,000,000		1,797,000,000
Revenues						8,875,000,000							34,532,000,000		16,891,000,000
Cost of services (exclusive of depreciation and amortization below)						2,622,000,000							9,660,000,000		5,174,000,000
Cost of products (exclusive of depreciation and amortization below)						2,038,000,000							9,309,000,000		4,603,000,000
Net operating expenses:
Selling, general and administrative						2,371,000,000							9,563,000,000		4,805,000,000
Depreciation						868,000,000							3,797,000,000		2,026,000,000
Amortization						429,000,000							1,552,000,000		908,000,000
Total costs and expenses						8,455,000,000							36,426,000,000		17,825,000,000
Operating (loss) income						420,000,000							(1,894,000,000)		(934,000,000)
Other (expense) income:
Interest and Other Income						4,000,000							3,000,000		6,000,000
Interest Expense						(166,000,000)							(667,000,000)		(407,000,000)
Equity in losses of unconsolidated investments, net													0
Gain on previously-held equity interests													0
(Losses) earnings of subsidiaries						0							0		0
Other nonoperating income (expense), excluding interest income						(3,000,000)							14,000,000		56,000,000
Nonoperating income (expense)						(165,000,000)							(650,000,000)		(345,000,000)
Income (loss) before income taxes						255,000,000							(2,544,000,000)		(1,279,000,000)
Income tax benefit (expense)						(56,000,000)							574,000,000		(41,000,000)
Net loss						199,000,000							(1,970,000,000)		(1,320,000,000)
Other comprehensive (loss) income						(147,000,000)							(355,000,000)		93,000,000
Comprehensive (loss)						52,000,000							(2,325,000,000)		(1,227,000,000)
Asset impairments						75,000,000							2,133,000,000
Severance and exit costs						52,000,000							304,000,000		309,000,000
Other, net													108,000,000
Successor [Member] | Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Service						0							0		0
Equipment						0							0		0
Revenues						0							0		0
Cost of services (exclusive of depreciation and amortization below)						0							0		0
Cost of products (exclusive of depreciation and amortization below)						0							0		0
Net operating expenses:
Selling, general and administrative						0							0		0
Depreciation						0							0		0
Amortization						0							0		0
Total costs and expenses						0							0		0
Operating (loss) income						0							0		0
Other (expense) income:
Interest and Other Income						(189,000,000)							(824,000,000)		(200,000,000)
Interest Expense						189,000,000							824,000,000		200,000,000
Equity in losses of unconsolidated investments, net													0
Gain on previously-held equity interests													0
(Losses) earnings of subsidiaries						(45,000,000)							5,315,000,000		3,151,000,000
Other nonoperating income (expense), excluding interest income						0							0		0
Nonoperating income (expense)						(45,000,000)							5,315,000,000		3,151,000,000
Income (loss) before income taxes						(45,000,000)							5,315,000,000		3,151,000,000
Income tax benefit (expense)						0							0		0
Net loss						(45,000,000)							5,315,000,000		3,151,000,000
Other comprehensive (loss) income						292,000,000							720,000,000		(195,000,000)
Comprehensive (loss)						247,000,000							6,035,000,000		2,956,000,000
Asset impairments						0							0
Severance and exit costs						0							0		0
Other, net													0
Successor [Member] | Parent [Member]
Condensed Income Statements, Captions [Line Items]
Service						0							0		0
Equipment						0							0		0
Revenues						0							0		0
Cost of services (exclusive of depreciation and amortization below)						0							0		0
Cost of products (exclusive of depreciation and amortization below)						0							0		0
Net operating expenses:
Selling, general and administrative						0							0		36,000,000
Depreciation						0							0		0
Amortization						0							0		0
Total costs and expenses						0							0		36,000,000
Operating (loss) income						0							0		(36,000,000)
Other (expense) income:
Interest and Other Income						169,000,000							687,000,000		189,000,000
Interest Expense						(166,000,000)							(687,000,000)		(163,000,000)
Equity in losses of unconsolidated investments, net													0
Gain on previously-held equity interests													0
(Losses) earnings of subsidiaries						(154,000,000)							(3,345,000,000)		(1,831,000,000)
Other nonoperating income (expense), excluding interest income						0							0		(15,000,000)
Nonoperating income (expense)						(151,000,000)							(3,345,000,000)		(1,820,000,000)
Income (loss) before income taxes						(151,000,000)							(3,345,000,000)		(1,856,000,000)
Income tax benefit (expense)						0							0		(4,000,000)
Net loss						(151,000,000)							(3,345,000,000)		(1,860,000,000)
Other comprehensive (loss) income						(145,000,000)							(365,000,000)		102,000,000
Comprehensive (loss)						(296,000,000)							(3,710,000,000)		(1,758,000,000)
Asset impairments						0							0
Severance and exit costs						0							0		0
Other, net													0
Predecessor [Member]
Condensed Income Statements, Captions [Line Items]
Service	16,895,000,000										7,980,000,000							32,097,000,000
Equipment	1,707,000,000										813,000,000							3,248,000,000
Revenues	18,602,000,000								8,877,000,000		8,793,000,000					932,000,000		35,345,000,000
Cost of services (exclusive of depreciation and amortization below)	5,673,000,000										2,640,000,000							10,936,000,000
Cost of products (exclusive of depreciation and amortization below)	4,872,000,000										2,293,000,000							9,905,000,000
Net operating expenses:
Selling, general and administrative	5,067,000,000										2,336,000,000							9,765,000,000
Severance, exit costs and asset impairments											25,000,000
Depreciation	3,098,000,000										1,422,000,000							6,240,000,000
Amortization	147,000,000										70,000,000							303,000,000
Total costs and expenses	19,487,000,000										8,764,000,000							37,165,000,000
Operating (loss) income	(885,000,000)								874,000,000		29,000,000					(40,000,000)		(1,820,000,000)
Other (expense) income:
Interest and Other Income	33,000,000										14,000,000							65,000,000
Interest Expense	(1,135,000,000)										(432,000,000)							(1,428,000,000)
Equity in losses of unconsolidated investments, net	(482,000,000)										(202,000,000)						(482,000,000)	(1,114,000,000)
Gain on previously-held equity interests	2,926,000,000										0							0
(Losses) earnings of subsidiaries	0										0							0
Other nonoperating income (expense), excluding interest income	(14,000,000)										(14,000,000)							125,000,000
Nonoperating income (expense)	1,328,000,000										(634,000,000)							(2,352,000,000)
Income (loss) before income taxes	443,000,000										(605,000,000)							(4,172,000,000)
Income tax benefit (expense)	(1,601,000,000)										(38,000,000)							(154,000,000)
Net loss	(1,158,000,000)								(1,597,000,000)		(643,000,000)					1,082,000,000		(4,326,000,000)
Other comprehensive (loss) income	23,000,000										14,000,000							(341,000,000)
Comprehensive (loss)	(1,135,000,000)										(629,000,000)							(4,667,000,000)
Asset impairments	0										0							102,000,000	[1]
Severance and exit costs	652,000,000										25,000,000							196,000,000
Other income (expense), net	19,000,000										0							190,000,000
Other, net	(22,000,000)										(22,000,000)							(282,000,000)
Predecessor [Member] | Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Service	0										0							0
Equipment	0										0							0
Revenues	0										0							0
Cost of services (exclusive of depreciation and amortization below)	0										0							0
Cost of products (exclusive of depreciation and amortization below)	0										0							0
Net operating expenses:
Selling, general and administrative	0										0							0
Depreciation	0										0							0
Amortization	0										0							0
Total costs and expenses	0										0							0
Operating (loss) income	0										0							0
Other (expense) income:
Interest and Other Income	61,000,000										29,000,000							112,000,000
Interest Expense	(842,000,000)										(292,000,000)							(907,000,000)
Equity in losses of unconsolidated investments, net	0										0							0
Gain on previously-held equity interests	0
(Losses) earnings of subsidiaries	(365,000,000)										(368,000,000)							(3,530,000,000)
Other nonoperating income (expense), excluding interest income	(12,000,000)										(12,000,000)							(1,000,000)
Nonoperating income (expense)	(1,158,000,000)										(643,000,000)							(4,326,000,000)
Income (loss) before income taxes	(1,158,000,000)										(643,000,000)							(4,326,000,000)
Income tax benefit (expense)	0										0							0
Net loss	(1,158,000,000)										(643,000,000)							(4,326,000,000)
Other comprehensive (loss) income	23,000,000										14,000,000							(341,000,000)
Comprehensive (loss)	(1,135,000,000)										(629,000,000)							(4,667,000,000)
Asset impairments																		0
Severance and exit costs	0										0							0
Other, net	0										0							0
Predecessor [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Income Statements, Captions [Line Items]
Service	16,895,000,000										7,980,000,000							32,097,000,000
Equipment	1,707,000,000										813,000,000							3,248,000,000
Revenues	18,602,000,000										8,793,000,000							35,345,000,000
Cost of services (exclusive of depreciation and amortization below)	5,673,000,000										2,640,000,000							10,936,000,000
Cost of products (exclusive of depreciation and amortization below)	4,872,000,000										2,293,000,000							9,905,000,000
Net operating expenses:
Selling, general and administrative	5,067,000,000										2,336,000,000							9,765,000,000
Depreciation	3,098,000,000										1,422,000,000							6,240,000,000
Amortization	147,000,000										70,000,000							303,000,000
Total costs and expenses	19,487,000,000										8,764,000,000							37,165,000,000
Operating (loss) income	(885,000,000)										29,000,000							(1,820,000,000)
Other (expense) income:
Interest and Other Income	15,000,000										6,000,000							34,000,000
Interest Expense	(336,000,000)										(161,000,000)							(602,000,000)
Equity in losses of unconsolidated investments, net	(482,000,000)										(202,000,000)							(1,114,000,000)
Gain on previously-held equity interests	2,926,000,000
(Losses) earnings of subsidiaries	0										0							0
Other nonoperating income (expense), excluding interest income	(2,000,000)										(2,000,000)							126,000,000
Nonoperating income (expense)	2,121,000,000										(359,000,000)							(1,556,000,000)
Income (loss) before income taxes	1,236,000,000										(330,000,000)							(3,376,000,000)
Income tax benefit (expense)	(1,601,000,000)										(38,000,000)							(154,000,000)
Net loss	(365,000,000)										(368,000,000)							(3,530,000,000)
Other comprehensive (loss) income	35,000,000										15,000,000							(339,000,000)
Comprehensive (loss)	(330,000,000)										(353,000,000)							(3,869,000,000)
Asset impairments																		102,000,000
Severance and exit costs	652,000,000										25,000,000							196,000,000
Other, net	(22,000,000)										(22,000,000)							(282,000,000)
Predecessor [Member] | Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Service	0										0							0
Equipment	0										0							0
Revenues	0										0							0
Cost of services (exclusive of depreciation and amortization below)	0										0							0
Cost of products (exclusive of depreciation and amortization below)	0										0							0
Net operating expenses:
Selling, general and administrative	0										0							0
Depreciation	0										0							0
Amortization	0										0							0
Total costs and expenses	0										0							0
Operating (loss) income	0										0							0
Other (expense) income:
Interest and Other Income	(43,000,000)										(21,000,000)							(81,000,000)
Interest Expense	43,000,000										21,000,000							81,000,000
Equity in losses of unconsolidated investments, net	0										0							0
Gain on previously-held equity interests	0
(Losses) earnings of subsidiaries	365,000,000										368,000,000							3,530,000,000
Other nonoperating income (expense), excluding interest income	0										0							0
Nonoperating income (expense)	365,000,000										368,000,000							3,530,000,000
Income (loss) before income taxes	365,000,000										368,000,000							3,530,000,000
Income tax benefit (expense)	0										0							0
Net loss	365,000,000										368,000,000							3,530,000,000
Other comprehensive (loss) income	(35,000,000)										(15,000,000)							339,000,000
Comprehensive (loss)	330,000,000										353,000,000							3,869,000,000
Asset impairments																		0
Severance and exit costs	0										0							0
Other, net	$ 0										$ 0							$ 0

[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.