Tower Obligations - Sale Leaseback Transaction (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Property and equipment, net
Sale Leaseback Transaction [Line Items]
Failed sale-leasebacks	$ 2,838	$ 198
Failed Sale Leaseback Transaction, Tower Obligations
Sale Leaseback Transaction [Line Items]
Failed sale-leasebacks	3,028	2,236
Other Noncurrent Liabilities
Sale Leaseback Transaction [Line Items]
Failed sale-leasebacks	$ 1,712	$ 0

The net book value of the asset(s) sold in connection with the sale of the property to another party and lease back to the seller.

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