Receivables and Related Allowance for Credit Losses - Schedule of Equipment Installment Plan Receivables (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) segment class	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio segments | segment	2
Customer classes | class	2
Net, migration change percentage	0.12
EIP receivables, gross	$ 7,271	$ 8,480
Unamortized imputed discount	(505)	(483)
EIP receivables, net of unamortized imputed discount	6,766	7,997
Allowance for credit losses	(268)	(328)
EIP receivables, net of allowance for credit losses and imputed discount	6,498	7,669
Equipment installment plan receivables, net of allowance for credit losses and imputed discount
Accounts, Notes, Loans and Financing Receivable [Line Items]
EIP receivables, net of allowance for credit losses and imputed discount	4,456	5,123
Equipment installment plan receivables due after one year, net of allowance for credit losses and imputed discount
Accounts, Notes, Loans and Financing Receivable [Line Items]
EIP receivables, net of allowance for credit losses and imputed discount	$ 2,042	$ 2,546
EIP Receivables Allowance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average effective imputed interest rate	10.60%	8.00%