Acquisitions and Dispositions (Allocation Of Acquisition Costs) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Cash	$ 682	$ 210
Estimated fair value of deferred/contingent consideration	29	17
Total consideration	711	227
Allocation of purchase price:
Goodwill	16,655	$ 15,576	$ 16,251	$ 16,317
Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Cash	682
Estimated fair value of deferred/contingent consideration	29
Total consideration	711
Allocation of purchase price:
Cash and cash equivalents	27
Cash and cash equivalents held in a fiduciary capacity	14
Net receivables	28
Other current assets	4
Goodwill	480
Other intangible assets	255
Fixed assets, net	2
Right of use assets	12
Other assets	1
Total assets acquired	823
Current liabilities	52
Fiduciary liabilities	14
Other liabilities	46
Total liabilities assumed	112
Net assets acquired	$ 711