Shareholders' Equity (Summary Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 4,893	$ 7,463	$ 7,886
Other comprehensive income before reclassifications, net of tax	88	(3,093)
Amounts reclassified from AOCI, net of tax	332	61
Other comprehensive income (loss), net of tax	420	(3,032)	(405)
Ending balance	5,691	4,893	7,463
Income tax expense included in other comprehensive income	137	(989)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,112)	(80)	325
Ending balance	(2,692)	(3,112)	(80)
Net unrealized gains (losses) on investment securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,800)	(78)
Other comprehensive income before reclassifications, net of tax	66	(2,762)
Amounts reclassified from AOCI, net of tax	208	40
Other comprehensive income (loss), net of tax	274	(2,722)
Ending balance	(2,526)	(2,800)	(78)
Income tax expense included in other comprehensive income	90	(888)
Net unrealized gains (losses) on derivatives and other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(311)	0
Other comprehensive income before reclassifications, net of tax	22	(332)
Amounts reclassified from AOCI, net of tax	124	21
Other comprehensive income (loss), net of tax	146	(311)
Ending balance	(165)	(311)	0
Income tax expense included in other comprehensive income	47	(101)
Pension and post-retirement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1)	(2)
Other comprehensive income before reclassifications, net of tax	0	1
Amounts reclassified from AOCI, net of tax	0	0
Other comprehensive income (loss), net of tax	0	1
Ending balance	(1)	(1)	$ (2)
Income tax expense included in other comprehensive income	$ 0	$ 0