Supplemental Disclosures to the Consolidated Statements of Cash Flows (Schedule of Supplemental Cash Flow Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash, and cash and cash equivalents held in a fiduciary capacity	$ 1,292	$ 734	$ 1,697
Acquisition-related deposit	0	24	0
Fiduciary liabilities assumed	(93)	(6)	(18)
Liabilities assumed	(182)	(49)	(213)
Non-controlling interests assumed	0	(5)	(64)
Fair value of previously-held equity method investment	0	(6)	(390)
Contingent/deferred purchase consideration	(41)	(120)	(153)
Net cash outflow for acquisitions	976	572	859
Interest paid	499	431	441
Income taxes paid, net of refunds	$ 1,119	$ 1,049	$ 1,069