Supplemental Disclosures to the Consolidated Statements of Cash Flows (Additional Information Concerning Acquisitions, Interest And Income Taxes Paid) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Information [Abstract]
Assets acquired, excluding cash	$ 0	$ 249
Liabilities assumed	0	(5)
Contingent/deferred purchase consideration	0	(44)
Net cash outflow for current year acquisitions	0	200
Interest paid	191	199
Income taxes paid, net of refunds	$ 122	$ 136