Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Latest date the outstanding debt instruments are required to be repaid, in CCYY-MM-DD format.

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Amount, after accumulated amortization, of debt discount (premium).

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

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Long-Term Debt, Financing and Capital Lease Obligations (Schedule of Long-term Debt Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Nov. 26, 2018	Nov. 01, 2018	Mar. 31, 2018	Feb. 20, 2018	Feb. 02, 2017	Oct. 31, 2016
Debt Instrument [Line Items]
Long-term debt, gross			$ 8,000				$ 6,000
Net premiums	$ (405)				$ (111)
Current and long-term debt, financing and capital lease obligations	39,923				40,892
Less current portion	(4,557)				(3,429)
Long-term debt, financing and capital lease obligations	$ 35,366				37,463
Senior Notes [Member] \| Sprint Corporation [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage						7.625%
Maturity date, start	Sep. 15, 2021
Maturity date, end	Mar. 01, 2026
Long-term debt, gross	$ 12,000				12,000
Senior Notes [Member] \| Sprint Capital Corporation [Member]
Debt Instrument [Line Items]
Maturity date, start	May 01, 2019
Maturity date, end	Mar. 15, 2032
Long-term debt, gross	$ 6,204				6,204
Senior Notes [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		9.25%
Maturity date, start	Aug. 15, 2020
Maturity date, end	Nov. 15, 2022
Long-term debt, gross	$ 4,780				4,980
Less current portion		$ (200)
Secured Notes [Member] \| Sprint Spectrum Co LLC, Sprint Spectrum Co II LLC, Sprint Spectrum Co III LLC [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage								3.36%
Maturity date, start	Sep. 20, 2021
Maturity date, end	Mar. 20, 2028
Long-term debt, gross	$ 6,125				7,000
Guaranteed Notes [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage				9.00%
Maturity date, start	Mar. 01, 2020
Long-term debt, gross	$ 1,000			$ 1,800	2,753
Revolving Credit Facility [Member] \| Unsecured Revolving Credit Facility expires in 2018 [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate	4.75%
Maturity date, end	Feb. 03, 2021
Line of credit facility, amount outstanding	$ 0				0
Secured term loan [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Maturity date, end	Feb. 03, 2024
Long-term debt, gross	$ 3,900		$ 2,000				$ 4,000
Line of credit facility, amount outstanding	$ 5,915				3,960
Secured term loan [Member] \| PRWireless HoldCo, LLC Secured Term Loan [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate	7.84%
Debt instrument, maturity date	Jun. 28, 2020
Line of credit facility, amount outstanding	$ 198				182
Receivable Facility, amount outstanding [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Maturity date, end	Jun. 29, 2020
Line of credit facility, amount outstanding	$ 2,607				2,411
Line of Credit [Member] \| Export Development Canada Credit Facilities [Member]
Debt Instrument [Line Items]
Maturity date, end	Dec. 17, 2019
Line of credit facility, amount outstanding	$ 300				300
Line of Credit [Member] \| Secured Equipment Credit Facilities [Member]
Debt Instrument [Line Items]
Maturity date, start	Dec. 21, 2020
Maturity date, end	Dec. 19, 2022
Line of credit facility, amount outstanding	$ 661				527
Line of Credit [Member] \| Financing Obligations, Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Maturity date, start	Jun. 01, 2019
Maturity date, end	Jun. 01, 2026
Financing Obligations, Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 538				$ 686
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 278
Minimum [Member] \| Senior Notes [Member] \| Sprint Corporation [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.13%
Minimum [Member] \| Senior Notes [Member] \| Sprint Capital Corporation [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.88%
Minimum [Member] \| Senior Notes [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.00%
Minimum [Member] \| Secured Notes [Member] \| Sprint Spectrum Co LLC, Sprint Spectrum Co II LLC, Sprint Spectrum Co III LLC [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.36%
Minimum [Member] \| Guaranteed Notes [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.00%
Minimum [Member] \| Secured term loan [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate	5.00%
Minimum [Member] \| Receivable Facility, amount outstanding [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.62%
Minimum [Member] \| Line of Credit [Member] \| Secured Equipment Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.13%
Minimum [Member] \| Financing Obligations, Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.35%
Maximum [Member] \| Senior Notes [Member] \| Sprint Corporation [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.88%
Maximum [Member] \| Senior Notes [Member] \| Sprint Capital Corporation [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.75%
Maximum [Member] \| Senior Notes [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	11.50%
Maximum [Member] \| Secured Notes [Member] \| Sprint Spectrum Co LLC, Sprint Spectrum Co II LLC, Sprint Spectrum Co III LLC [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.15%
Maximum [Member] \| Secured term loan [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate	5.50%
Maximum [Member] \| Receivable Facility, amount outstanding [Member] \| Sprint Nextel Corporation Guaranteed Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.82%
Maximum [Member] \| Line of Credit [Member] \| Export Development Canada Credit Facilities [Member]
Debt Instrument [Line Items]
Percentage bearing variable interest, percentage rate	4.75%
Maximum [Member] \| Line of Credit [Member] \| Secured Equipment Credit Facilities [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.86%
Maximum [Member] \| Financing Obligations, Capital Lease Obligations and Other [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	12.00%