Fair Value Measurements And Disclosure (Gain and Losses on Equity Securities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Total gains (losses) recognized on equity securities	$ (58)	$ (79)	$ 107	$ (411)
Gains (losses) recognized on equity securities sold	(2)	(8)	(1)	(56)
Unrealized gains (losses) recognized on equity securities held at end of period	$ (56)	$ (71)	$ 108	$ (355)