Equipment Installment Plans - Allowance for Credit Losses (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Allowance for credit losses
Allowance for credit losses, beginning of period	$ 96
Allowance for credit losses, end of period	92
Equipment Installment Plan Receivable
Allowance for credit losses
Write-offs, net of recoveries, originated in 2020	1
Write-offs, net of recoveries, originated in 2021	9
Write-offs, net of recoveries, originated in 2022	28
Write-offs, net of recoveries, originated in 2023	1
Write-offs, net of recoveries, Total	39	$ 35
Allowance for credit losses, beginning of period	96	72
Bad debts expense	35	37
Write-offs, net of recoveries	(39)	(35)
Allowance for credit losses, end of period	$ 92	$ 74