Long-Term Debt, Financing and Capital Lease Obligations (Narrative) (Details) site in Thousands		3 Months Ended			6 Months Ended	12 Months Ended
		Dec. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Mar. 31, 2013 USD ($)	Jul. 10, 2013 USD ($)	Mar. 31, 2016 USD ($) site years	Mar. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)	Nov. 19, 2015 USD ($)	Sep. 30, 2015 USD ($)	Feb. 24, 2015 USD ($)	Dec. 31, 2014 USD ($) tranche	Dec. 12, 2013 USD ($)	Sep. 11, 2013 USD ($)	Apr. 02, 2013 USD ($)
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt issued by 100% owned subsidiary and is fully and unconditionally guaranteed by the parent						$ 21,600,000,000
Secured debt						2,100,000,000
Secured Debt Collateral						15,800,000,000
Cash interest payments						2,400,000,000
Redeemable notes						30,100,000,000
Principal amount of notes with the right to require the Company to repurchase on change of control						$ 21,600,000,000
Percentage of principal amount required to repurchase notes on change of control						101.00%
Fixed amount of cash for a fixed principal amount of notes surrendered that becomes exchangeable at the holder's option					$ 706.21
Fixed principal amount of notes surrendered for a fixed amount of cash that becomes exchangeable at the holder's option					1,000
Number of cell sites leased back | site						3
Term in years for cell sites leased back renewal options | years						20
Derecognized assets, gross										$ 1,900,000,000
Ratio of total indebtedness to adjusted EBITDA						2.5
Sale Leaseback Transaction, Net Book Value		$ 1,300,000,000				$ 1,200,000,000			$ 1,300,000,000
Exchangeable Notes [Member] | Clearwire Communications LLC [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross					$ 629,000,000
Debt instrument, interest rate, stated percentage					8.25%
Total cash consideration payable upon an exchange of all principal amount of notes outstanding					$ 444,000,000
Secured Notes [Member] | Clearwire Communications LLC [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Principal amount of notes with the right to require the Company to repurchase on change of control						300,000,000
Senior Notes [Member] | Sprint Communications Inc. Guaranteed Notes due 2021 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Debt instrument, interest rate, stated percentage											7.625%			7.25%
Debt instrument, face amount											$ 1,500,000,000			$ 2,250,000,000
Senior Notes [Member] | Sprint Corporation 7.875% [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Debt instrument, interest rate, stated percentage														7.875%
Debt instrument, face amount														$ 4,250,000,000
Senior Notes [Member] | Sprint Corporation 7.125% [Member] [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Debt instrument, interest rate, stated percentage													7.125%
Debt instrument, face amount													$ 2,500,000,000
Line of Credit [Member] | Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Debt instrument, annual principal payment						254,000,000
Line of Credit [Member] | Finnvera Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity												$ 800,000,000
Debt instrument, annual principal payment						56,000,000
Number of tranches | tranche												3
Line of Credit [Member] | K-sure Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity												$ 750,000,000
Line of credit facility, amount outstanding						323,000,000
Number of tranches | tranche												3
Line of Credit [Member] | Delcredere / Ducroire (D/D) Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity												$ 250,000,000
Line of credit facility, amount outstanding						32,000,000
Line of Credit Facility, Increase (Decrease), Net						32,000,000
Revolving Credit Facility [Member] | Unsecured Revolving Credit Facility expires in 2018 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity															$ 3,300,000,000
Line of Credit Facility, Remaining Borrowing Capacity						3,000,000,000
Letter of Credit [Member] | Unsecured Revolving Credit Facility expires in 2018 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Letters of credit outstanding, amount						320,000,000
Successor [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Interest costs capitalized			$ 13,000,000			$ 51,000,000	$ 56,000,000	$ 30,000,000
Cash interest payments			$ 559,000,000				$ 2,300,000,000	$ 1,000,000,000
Senior notes weighted average effective interest rate			6.20%			6.40%	6.10%	6.40%
Successor [Member] | Exchangeable Notes [Member] | Clearwire Communications LLC [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross	[1]					$ 629,000,000	$ 629,000,000
Debt instrument, interest rate, stated percentage	[1]					8.25%
Successor [Member] | Secured Notes [Member] | Clearwire Communications LLC [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross	[1]					$ 300,000,000	300,000,000
Debt instrument, interest rate, stated percentage	[1]					14.75%
Successor [Member] | Senior Notes [Member] | Sprint Corporation [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross						$ 10,500,000,000	10,500,000,000
Successor [Member] | Senior Notes [Member] | Sprint Nextel Corporation Guaranteed Notes [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross						9,280,000,000	9,280,000,000
Successor [Member] | Line of Credit [Member] | Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, amount outstanding						254,000,000
Successor [Member] | Line of Credit [Member] | Finnvera Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, amount outstanding						196,000,000
Successor [Member] | Line of Credit [Member] | K-sure Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Increase (Decrease), Net						266,000,000
Successor [Member] | Guaranteed Notes [Member] | Sprint Nextel Corporation Guaranteed Notes [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross						4,000,000,000	4,000,000,000
Successor [Member] | Revolving Credit Facility [Member] | Unsecured Revolving Credit Facility expires in 2018 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, amount outstanding						0	$ 0
Predecessor [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Interest costs capitalized				$ 15,000,000	29,000,000
Cash interest payments				$ 305,000,000	$ 814,000,000
Senior notes weighted average effective interest rate				7.10%	8.90%
Tranche one [Member] | Line of Credit [Member] | Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, amount outstanding						1,000,000,000
Tranche one [Member] | Line of Credit [Member] | Finnvera Secured Equipment Credit Facility [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of Credit Facility, Increase (Decrease), Net						208,000,000
Parent [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Long-term debt, gross						10,500,000,000
Export Development Canada Credit Facilities [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Repayments of Lines of Credit		500,000,000
Line of credit facility, amount outstanding						$ 550,000,000
Export Development Canada Credit Facilities [Member] | Tranche three [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 250,000,000
Unsecured Revolving Credit Facility expires in 2018 [Member]
Schedule of Capitalization, Long-term Debt [Line Items]
Ratio of total indebtedness to adjusted EBITDA through the quarter ended December 31, 2016						6.25
Required ratio of total indebtedness to adjusted EBITDA for each fiscal quarter ending thereafter through expiration of the revolving credit facility						6.0
Minimum required cash remaining on hand for operations as part of covenants						$ 2,000,000,000

[1] (1)Notes of Clearwire Communications LLC are also direct obligations of Clearwire Finance, Inc. and are guaranteed by certain Clearwire subsidiaries.