Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Supplemental disclosures of cash flow information:
Cash and cash equivalents		$ 1,507	$ 1,893	$ 1,890
Fiduciary funds (included in fiduciary assets)		3,476	3,358
Total cash, cash equivalents and restricted cash		4,983	5,251
(Decrease)/increase in cash, cash equivalents and other restricted cash	[1]	(95)	1,506
Non-Fiduciary [Member]
Supplemental disclosures of cash flow information:
(Decrease)/increase in cash, cash equivalents and other restricted cash		(411)	487
Fiduciary [Member]
Supplemental disclosures of cash flow information:
(Decrease)/increase in cash, cash equivalents and other restricted cash		$ 316	$ 1,019

[1] The amounts of cash, cash equivalents and restricted cash, their respective classification on the condensed consolidated balance sheets as well as their respective portions of the increase or decrease in cash, cash equivalents and restricted cash for each of the periods presented have been included in Note 19 — Supplemental Disclosures of Cash Flow Information.