Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash and cash and cash equivalents held in a fiduciary capacity	$ 164	$ 561
Acquisition-related deposit	24	0
Fiduciary liabilities assumed	(2)	(13)
Liabilities assumed	(24)	(60)
Contingent/deferred purchase consideration	(11)	(138)
Net cash outflow for acquisitions	151	350
Interest paid	215	234
Income taxes paid, net of refunds	$ 437	$ 403