Goodwill And Other Intangible Assets (Schedule Of Change In Goodwill) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment of goodwill and intangible assets		$ 0
Goodwill [Roll Forward]
Balance at January 1, 2021	$ 1,798,408,000
Additions	1,656,949,000
Other	0
Balance at March 31, 2021	$ 3,455,357,000	$ 1,798,408,000