Acquisitions and Dispositions (Allocation Of Acquisition Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Cash	$ 1,100	$ 579
Estimated fair value of deferred/contingent consideration	41	120	$ 153
Total consideration	1,200	705
Allocation of purchase price:
Goodwill	17,231	$ 16,251	$ 16,317
Current Fiscal Period Acquisitions
Business Acquisition [Line Items]
Cash	1,140
Estimated fair value of deferred/contingent consideration	41
Total consideration	1,181
Allocation of purchase price:
Cash and cash equivalents	48
Cash and cash equivalents held in a fiduciary capacity	93
Net receivables	46
Other current assets	9
Goodwill	813
Other intangible assets	427
Fixed assets, net	3
Right of use assets	17
Total assets acquired	1,456
Current liabilities	68
Fiduciary liabilities	93
Other liabilities	114
Total liabilities assumed	275
Net assets acquired	$ 1,181