Significant Accounting Policies - Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents	$ 4,183	$ 4,225
Restricted cash and cash equivalents	1,391	1,436
Total cash, cash equivalents and restricted cash and cash equivalents in the consolidated statements of cash flows	$ 5,574	$ 5,661	$ 5,851	$ 5,805