Intangible Assets - Narrative (Details) $ in Millions	12 Months Ended				42 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) license	Dec. 31, 2021 USD ($) license	Dec. 31, 2020 USD ($)	Mar. 31, 2025 USD ($)
Licenses
Cash paid for licenses	$ 130	$ 585	$ 1,302
Auction 107
Licenses
Licenses won | license			254
Total winning bid			$ 1,283
FCC Upfront Payment				$ 30
Cash paid for licenses	122	8	36
Auction 107 | Other current liabilities
Licenses
Short-term spectrum license liabilities	$ 13	133
Auction 107 | Other deferred liabilities and credits
Licenses
Long-term spectrum license liabilities		$ 8
Auction 107 | Subsequent event
Licenses
Cash paid for licenses					$ 179
Auction 110
Licenses
Licenses won | license		380
Total winning bid		$ 580
FCC Upfront Payment			$ 20