Investment Securities (Schedule Of Realized Gain (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Securities, Available-for-sale [Abstract]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities			$ 0	$ 0
Available-for-sale securities, gross realized gains	$ 24	$ 1	34	7
Available-for-sale securities, gross realized losses	0	0	(1)	0
Net realized gains on available-for-sale securities	24	1	33	7
Net realized gain on equity securities	10	18	39	40
Net unrealized gain (loss) on equity securities	5	8	75	(32)
Other gain on investments, net	$ 39	$ 27	$ 147	$ 15