Related Party Transactions Related Party Transactions (Details) (USD $)		0 Months Ended		3 Months Ended				6 Months Ended					3 Months Ended	6 Months Ended
	Jul. 08, 2013 Clearwire [Member]	Jul. 08, 2013 Predecessor [Member]	Jul. 10, 2013 Predecessor [Member]	Jul. 09, 2013 Predecessor [Member]	Jul. 10, 2013 Predecessor [Member]	Sep. 30, 2014 Successor [Member]	Sep. 30, 2013 Successor [Member]	Sep. 30, 2014 Successor [Member]	Sep. 30, 2013 Successor [Member]	Jul. 08, 2013 Non-controlling economic interest [Member] Clearwire Corporation [Member]	Jul. 08, 2013 Non-controlling economic interest [Member] Clearwire Communications LLC [Member]	Jul. 08, 2013 Non-controlling economic interest [Member] Clearwire Acquisition [Member]	Sep. 30, 2014 Equipment [Member] Successor [Member]	Sep. 30, 2014 Equipment [Member] Successor [Member]	Oct. 31, 2014 Subsequent Event [Member] Line of Credit [Member] Brightstar [Member]
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage										6.00%	44.10%	50.10%
Equity Method Investments	$ 325,000,000
Income (Loss) from Equity Method Investments		(23,000,000)	(23,000,000)	(280,000,000)	(280,000,000)	0	0	0	0
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		65,000,000		65,000,000
Related Party Transaction, Amounts of Transaction		11,000,000		106,000,000									1,300,000,000	2,700,000,000
Line of Credit Facility, Maximum Borrowing Capacity															$ 1,000,000,000