Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 601	$ 795
Liabilities assumed	(59)	(73)
Contingent/deferred purchase consideration	(141)	(163)
Net cash outflow for current year acquisitions	401	559
Interest paid	407	437
Income taxes paid, net of refunds	$ 686	$ 414