Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities, gross realized gains	$ 44	$ 45	$ 82	$ 169
Available-for-sale securities, gross realized losses	0	(2)	0	(2)
Net realized gains on available-for-sale securities	44	43	82	167
Net realized gain on equity securities	45	7	159	88
Net unrealized (loss) gain on equity securities	(65)	14	(29)	(82)
Other gain on investments, net	$ 24	$ 64	$ 212	$ 173