Debt - Receivables Securitization Agreement (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Equipment installment plan receivables		$ 1,151	$ 1,211
Receivables securitization agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		450
Amount repaid during the period		440
Amount borrowed during the period		315
Amounts borrowed and outstanding		150
Amount available for use		$ 300
Receivables securitization agreement | Lender's cost of funds
Debt Instrument [Line Items]
Contractual spread		1.15%
Receivables securitization agreement | Subsequent event
Debt Instrument [Line Items]
Amount repaid during the period	$ 50
Receivables securitization agreement | Assets pledged
Debt Instrument [Line Items]
Equipment installment plan receivables		$ 304