Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities - Schedule of Reconciliation of Cash and Cash Equivalents Inclusive of Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Cash Flow Elements [Abstract]
Restricted fiduciary cash	$ 1,570	$ 1,412	$ 1,232
Non-restricted fiduciary cash	257	191	151
Total restricted and non-restricted fiduciary cash at the end of the period	1,827	1,603	1,383
Cash and cash equivalents	675	700	650
Fiduciary cash	1,827	1,603	1,383
Total cash and cash equivalents inclusive of fiduciary cash at the end of the period	$ 2,502	$ 2,303	$ 2,033	$ 1,470