Segment Information (Operating Revenues by Service and Products) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Successor [Member]
Segment Reporting Information [Line Items]
Net operating revenues	$ 8,789		$ 0
Segment Reporting Information, Total Net Operating Revenues	8,789		0
Successor [Member] | Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	6,908
Successor [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	1,106
Successor [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	236
Successor [Member] | Data [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	32
Successor [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	307
Successor [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues	200
Successor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Net operating revenues	8,193
Segment Reporting Information, Total Net Operating Revenues	8,193		0
Successor [Member] | Wireless [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	6,908
Successor [Member] | Wireless [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues	1,106
Successor [Member] | Wireless [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0
Successor [Member] | Wireless [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0
Successor [Member] | Wireless [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0
Successor [Member] | Wireless [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	179
Successor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Net operating revenues	746
Segment Reporting Information, Total Net Operating Revenues	593		0
Successor [Member] | Wireline [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0
Successor [Member] | Wireline [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0
Successor [Member] | Wireline [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues	327
Successor [Member] | Wireline [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues	56
Successor [Member] | Wireline [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues	345
Successor [Member] | Wireline [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	18
Successor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Net operating revenues	(150)	[1]
Segment Reporting Information, Total Net Operating Revenues	3		0
Successor [Member] | Corporate, Other And Eliminations [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0	[1]
Successor [Member] | Corporate, Other And Eliminations [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues	0	[1]
Successor [Member] | Corporate, Other And Eliminations [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues	(91)	[1]
Successor [Member] | Corporate, Other And Eliminations [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues	(24)	[1]
Successor [Member] | Corporate, Other And Eliminations [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues	(38)	[1]
Successor [Member] | Corporate, Other And Eliminations [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues	3	[1]
Predecessor [Member]
Segment Reporting Information [Line Items]
Net operating revenues			8,877
Segment Reporting Information, Total Net Operating Revenues			8,877
Predecessor [Member] | Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			7,227
Predecessor [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			820
Predecessor [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			255
Predecessor [Member] | Data [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			43
Predecessor [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			384
Predecessor [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Information, Total Net Operating Revenues			148
Predecessor [Member] | Wireless [Member]
Segment Reporting Information [Line Items]
Net operating revenues			8,178
Segment Reporting Information, Total Net Operating Revenues			8,178
Predecessor [Member] | Wireless [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			7,227
Predecessor [Member] | Wireless [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues			820
Predecessor [Member] | Wireless [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0
Predecessor [Member] | Wireless [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0
Predecessor [Member] | Wireless [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0
Predecessor [Member] | Wireless [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			131
Predecessor [Member] | Wireline [Member]
Segment Reporting Information [Line Items]
Net operating revenues			910
Segment Reporting Information, Total Net Operating Revenues			695
Predecessor [Member] | Wireline [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0
Predecessor [Member] | Wireline [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0
Predecessor [Member] | Wireline [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues			377
Predecessor [Member] | Wireline [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues			87
Predecessor [Member] | Wireline [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues			432
Predecessor [Member] | Wireline [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			14
Predecessor [Member] | Corporate, Other And Eliminations [Member]
Segment Reporting Information [Line Items]
Net operating revenues			(211)	[1]
Segment Reporting Information, Total Net Operating Revenues			4
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0	[1]
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Equipment [Member]
Segment Reporting Information [Line Items]
Net operating revenues			0	[1]
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Voice [Member]
Segment Reporting Information [Line Items]
Net operating revenues			(122)	[1]
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Data [Member]
Segment Reporting Information [Line Items]
Net operating revenues			(44)	[1]
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Internet [Member]
Segment Reporting Information [Line Items]
Net operating revenues			(48)	[1]
Predecessor [Member] | Corporate, Other And Eliminations [Member] | Other Products or Services [Member]
Segment Reporting Information [Line Items]
Net operating revenues			$ 3	[1]

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