Segment Information (Segment Financial Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Mar. 31, 2014
Segment Reporting Information [Line Items]
Number of Reportable Segments	2
Predecessor [Member]
Segment Reporting Information [Line Items]
Business Combination, Acquisition Related Costs			$ (34)
Segment Reporting Information, Total Net Operating Revenues			8,877
Revenues			8,877
Segment Operating Expenses			(7,453)
Segment Reporting Information Operating Income or Loss			1,424
Depreciation			1,563
Amortization			69
Other, net			(666)	[1]
Interest Expense			(428)
Equity in losses of unconsolidated investments, net			(257)
Income loss from equity method investments, net			(257)
Other income (expense), net			17
Loss (income) before income taxes			(1,542)
Severance, exit costs and asset impairments			(632)
Payments to Acquire Property, Plant, and Equipment			1,571
Predecessor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			8,178
Revenues			8,178
Segment Operating Expenses			(6,884)
Segment Reporting Information Operating Income or Loss			1,294
Payments to Acquire Property, Plant, and Equipment			1,403
Predecessor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			695
Revenues			910
Segment Operating Expenses			(781)
Segment Reporting Information Operating Income or Loss			129
Payments to Acquire Property, Plant, and Equipment			100
Predecessor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			4
Revenues			(211)	[2]
Segment Operating Expenses			212
Segment Reporting Information Operating Income or Loss			1
Payments to Acquire Property, Plant, and Equipment			68
Successor [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	(27)
Segment Reporting Information, Total Net Operating Revenues	8,789		0
Revenues	8,789		0
Segment Operating Expenses	(6,962)		22
Segment Reporting Information Operating Income or Loss	1,827		(22)
Depreciation	868		0
Amortization	413		0
Other, net	(27)	[1]
Interest Expense	(512)		0
Equity in losses of unconsolidated investments, net	0		0
Other income (expense), net	1		(153)
Loss (income) before income taxes	8		(175)
Severance, exit costs and asset impairments	(27)		0
Payments to Acquire Property, Plant, and Equipment	1,246		0
Assets	84,419				84,689
Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	8,193		0
Revenues	8,193
Segment Operating Expenses	(6,400)		0
Segment Reporting Information Operating Income or Loss	1,793		0
Payments to Acquire Property, Plant, and Equipment	1,120
Successor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	593		0
Revenues	746
Segment Operating Expenses	(711)		0
Segment Reporting Information Operating Income or Loss	35		0
Payments to Acquire Property, Plant, and Equipment	59
Successor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	3		0
Revenues	(150)	[2]
Segment Operating Expenses	149		(22)
Segment Reporting Information Operating Income or Loss	(1)		(22)
Payments to Acquire Property, Plant, and Equipment	67
Successor [Member] | Lease [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Restructuring Charges	(3)	[3]
Intersegment Eliminations [Member] | Predecessor [Member]
Segment Reporting Information [Line Items]
Revenues			0	[4]
Intersegment Eliminations [Member] | Predecessor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Revenues			0	[4]
Intersegment Eliminations [Member] | Predecessor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Revenues			215	[4]
Intersegment Eliminations [Member] | Predecessor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues			(215)	[4]
Intersegment Eliminations [Member] | Successor [Member]
Segment Reporting Information [Line Items]
Revenues	0	[4]	0
Intersegment Eliminations [Member] | Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Revenues	0	[1]	0	[4]
Intersegment Eliminations [Member] | Successor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Revenues	153	[1]	0	[4]
Intersegment Eliminations [Member] | Successor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	$ (153)	[4]	$ 0	[4]

[1] (2)Other, net for the Successor three-month period ended June 30, 2014 consists of $27 million of severance and exit costs. Other, net for the Predecessor three-month period ended June 30, 2013 consists of $632 million of severance and exit costs and $34 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).

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

[3] (1)For the Successor three-month period ended June 30, 2014, we recognized costs of $3 million (solely attributable to Wireless).

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