Related Party Transactions (Brightstar) (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Related Party Transaction [Line Items]
Total revenue	$ 8,142	$ 8,125
Cost of equipment sales	1,341	1,270
Brightstar [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Other Revenues from Transactions with Related Party	42	49
Accounts Receivable, Related Parties	175		$ 187
Accounts Payable, Related Parties, Current	93		$ 109
Total revenue	344	413
Cost of equipment sales	$ 361	$ 432

Cost of equipment sales

No definition available.

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Amount for accounts payable 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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For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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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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Reflects the sum of all other revenue and income realized from sales and other transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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