Funding Sources (Details) - USD ($) $ in Millions	1 Months Ended					3 Months Ended	12 Months Ended
	Mar. 31, 2017	Feb. 28, 2017	Dec. 31, 2016	Oct. 31, 2016	Apr. 30, 2016	Dec. 31, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Feb. 02, 2017	May 31, 2016	Nov. 30, 2015	Nov. 19, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price from sale of receivables							$ (289)	$ 2,478	$ 0
cash paid to purchasers under receivables facility							270
Maximum funding limit												$ 4,300
Receivables Facility, Amount of Funds Available	$ 826						$ 826
Receivables Facility, maximum amount available based on receivables sold to investors, percent	50.00%						50.00%
Sale Leaseback Transaction, Net Book Value						$ 1,300							$ 1,300
Proceeds from sale-leaseback transaction						1,100	$ 0	1,136	$ 0
Receivables from sale-leaseback						$ 126
Gain (Loss) on Disposition of Property Plant Equipment								65
Sale Leaseback Transaction, Monthly Rental Payments							494	277
Long-term debt, gross										$ 6,000
Installment receivables, net	$ 1,764						1,764
Installment Lease Receivables, Net Book Value	3,100						3,100
Accounts and notes receivable, net	4,138						4,138	1,099
Other assets	1,313						1,313	728
Long-term debt, financing and capital lease obligations	35,878						35,878	29,268
Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
cash paid to purchasers under receivables facility	161
Cash received for sale of receivables under receivables facility	100						625
Cash Flows Between Transferor and Transferee, Proceeds from Collections Reinvested in Revolving Period Transfers							644
Network Sale-Leaseback [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale-leaseback transaction					$ 2,200
Sale Leaseback Transaction, Net Book Value	2,400				3,000		2,400
Repayments of Debt							300
Long-term Debt and Capital Lease Obligations, Repayments of Principal in Next Twelve Months	1,900						1,900
Leased handset [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables from sale-leaseback													$ 126
Sale Leaseback Transaction, Cash Payment For Retirement			$ 375
Property, Plant and Equipment, Additions			477
Additions to Other Assets, Amount			$ 16
MLS 2nd Tranche [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sale Leaseback Transaction, Net Book Value	385						385				$ 1,300
Proceeds from sale-leaseback transaction					1,100
Receivables from sale-leaseback					$ 186
Handset Sale-Leaseback Tranche 2 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sale Leaseback Transaction, Net Book Value	575						575
Secured Notes [Member] | Sprint Spectrum Co LLC, Sprint Spectrum Co II LLC, Sprint Spectrum Co III LLC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt instrument, face amount				$ 3,500
Long-term debt, gross	$ 3,500						$ 3,500	0
Debt Instrument, Term				5 years
Debt instrument, interest rate, stated percentage	3.36%			3.36%			3.36%
Secured Notes [Member] | Spectrum Financing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Instrument, Maximum Borrowing Capacity				$ 7,000
Debt Instrument, Additional Borrowings Available				$ 3,500
Secured term loan [Member] | Sprint Nextel Corporation Guaranteed Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Long-term debt, gross										4,000
Debt Instrument, Term		7 years
Revolving Credit Facility [Member] | Secured Revolving Bank Credit Facility expires in Feb 2021[Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Line of credit facility, maximum borrowing capacity										$ 2,000
Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price from sale of receivables								$ 1,200
Accounts and notes receivable, Net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment receivables, net	$ 1,195						$ 1,195
Other Noncurrent Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment receivables, net	569						$ 569
Spectrum Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Percentage				14.00%
Wireless Service [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase Commitment Allocation							33.00%
Installment Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase Commitment Allocation							39.00%
Future lease receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase Commitment Allocation							28.00%
Wireless Services and Installment Receivables [Member] | Accounts and notes receivable, Net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Installment receivables, net	$ 2,900						$ 2,900
Receivables Facility Adjustment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred purchase price from sale of receivables		$ (1,500)
Accounts and notes receivable, net		2,600
Other assets		563
Long-term debt, financing and capital lease obligations		$ (1,700)