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Business Combination, Required Financing Fees by Acquirer to Third Party Note Holders Upon Consummation

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The amount for notes payable (written promise to pay), due to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).

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The cash inflow from a long-term borrowing made from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Proceeds from Advances from Affiliates.

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Debt - Debt Balances and Activity (Details) - USD ($)				3 Months Ended			6 Months Ended
Debt - Debt Balances and Activity (Details) - USD ($)	Apr. 09, 2020	Apr. 01, 2020	May 18, 2018	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 24, 2020
Debt Balances and Activity [Roll Forward]
Long-term debt, beginning balance							$ 10,958,000,000
Proceeds from Issuances and Borrowings				$ 18,743,000,000	$ 0		18,743,000,000	$ 0
Proceeds from Issuances and Borrowings							45,433,000,000
Assumed Debt				38,000,000	50,000,000		38,000,000	300,000,000
Note Redemptions				(2,704,000,000)			(2,704,000,000)
Repayments				(18,929,000,000)	0		(18,929,000,000)	0
Repayments				(10,529,000,000)	(600,000,000)		(10,529,000,000)	(600,000,000)
Long-term debt, ending balance				62,783,000,000			62,783,000,000
Repayments of short-term debt				18,929,000,000	$ 0		18,929,000,000	$ 0
Principal Issuances				46,000,000,000			46,000,000,000
Senior Notes
Debt Balances and Activity [Roll Forward]
Proceeds from Issuances and Borrowings	$ 18,800,000,000
Principal Issuances	$ 19,000,000,000.0								$ 4,000,000,000.0
Sprint
Debt Balances and Activity [Roll Forward]
Total debt, ending balance				29,035,000,000			29,035,000,000
Principal Issuances				26,649,000,000			26,649,000,000
Sprint \| Senior Notes
Debt Balances and Activity [Roll Forward]
Payments for requisite consents to third-party note holders			$ 95,000,000			$ 54,000,000
Total Debt
Debt Balances and Activity [Roll Forward]
Total debt, beginning balance							24,969,000,000
Proceeds from Issuances and Borrowings							45,363,000,000
Assumed Debt							31,797,000,000
Note Redemptions				(26,790,000,000)			(26,790,000,000)
Repayments							(2,704,000,000)
Reclassifications							0
Other							(93,000,000)
Total debt, ending balance				72,542,000,000			72,542,000,000
Vendor Financing Arrangement
Debt Balances and Activity [Roll Forward]
Principal Issuances		$ 38,000,000
Affiliates
Debt Balances and Activity [Roll Forward]
Note Redemptions				(27,000,000,000)			(27,000,000,000)
Third Party \| Total Debt
Debt Balances and Activity [Roll Forward]
Total debt to third parties, beginning balance							10,983,000,000
Proceeds from Issuances and Borrowings							45,376,000,000
Assumed Debt							31,797,000,000
Note Redemptions				(18,749,000,000)			(18,749,000,000)
Repayments							(2,704,000,000)
Reclassifications							0
Other							(102,000,000)
Total debt to third parties, ending balance				66,601,000,000			66,601,000,000
DT \| Sprint
Debt Balances and Activity [Roll Forward]
Payments for requisite consents to DT		13,000,000
DT \| Affiliates \| Sprint \| Senior Notes
Debt Balances and Activity [Roll Forward]
Proceeds from Issuances and Borrowings		$ 4,000,000,000.0
Short-term Debt \| Affiliates
Debt Balances and Activity [Roll Forward]
Short-term debt to affiliates, beginning balance							0
Proceeds from Issuances and Borrowings							0
Assumed Debt							0
Note Redemptions				(2,000,000,000)			(2,000,000,000)
Repayments							0
Reclassifications							3,231,000,000
Other							4,000,000
Short-term debt to affiliates, ending balance				1,235,000,000			1,235,000,000
Short-term Debt \| Third Party
Debt Balances and Activity [Roll Forward]
Short-term debt, beginning balance							25,000,000
Proceeds from Issuances and Borrowings							18,782,000,000
Assumed Debt							2,760,000,000
Note Redemptions				(18,749,000,000)			(18,749,000,000)
Repayments							(394,000,000)
Reclassifications							1,395,000,000
Other							(1,000,000)
Short-term debt, ending balance				3,818,000,000			3,818,000,000
Repayments of short-term debt							394,000,000
Long-term debt \| Affiliates
Debt Balances and Activity [Roll Forward]
Long-term debt to affiliates, beginning balance							13,986,000,000
Proceeds from Issuances and Borrowings							(13,000,000)
Assumed Debt							0
Note Redemptions				(6,041,000,000)			(6,041,000,000)
Repayments							0
Reclassifications							(3,231,000,000)
Other							5,000,000
Long-term debt to affiliates, ending balance				4,706,000,000			4,706,000,000
Long-term debt \| Third Party
Debt Balances and Activity [Roll Forward]
Long-term debt, beginning balance							10,958,000,000
Proceeds from Issuances and Borrowings							26,594,000,000
Assumed Debt							29,037,000,000
Note Redemptions				0			0
Repayments							(2,310,000,000)
Reclassifications							(1,395,000,000)
Other							(101,000,000)
Long-term debt, ending balance				$ 62,783,000,000			$ 62,783,000,000