Transaction with MetroPCS (Condensed Consolidated Statements of Comprehensive Income (Loss) for MetroPCS Operations) (Details) (MetroPCS [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	5 Months Ended
Sep. 30, 2013	Sep. 30, 2013
MetroPCS [Member]
Business Acquisition [Line Items]
Total revenues	$ 1,273	$ 2,072
Income before income taxes	$ 87	$ 103

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration