Credit Quality And Allowance For Credit Losses (Changes In The Allowance For Loan Losses And Related Loan Amounts) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 728	$ 609	$ 661	$ 618
Provision for credit losses	14	28	77	27
Balance at end of period	$ 736	$ 624	$ 736	$ 624
As a percentage of total loans	1.38%	1.21%	1.38%	1.21%
Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 684	$ 563	$ 610	$ 588
Loan charge-offs	(14)	(26)	(37)	(57)
Recoveries on loans previously charged-off	8	13	35	36
Net loan (charge-offs) recoveries	(6)	(13)	(2)	(21)
Provision for credit losses	16	26	86	9
Balance at end of period	$ 694	$ 576	$ 694	$ 576
As a percentage of total loans	1.30%	1.11%	1.30%	1.11%
Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 44	$ 46	$ 51	$ 30
Provision for credit losses	(2)	2	(9)	18
Balance at end of period	42	48	42	48
Business loans:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	648	536	581	555
Provision for credit losses	17	26	79	16
Balance at end of period	$ 659	$ 549	$ 659	$ 549
As a percentage of total loans	1.34%	1.15%	1.34%	1.15%
Business loans: | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 614	$ 502	$ 541	$ 531
Loan charge-offs	(13)	(25)	(34)	(55)
Recoveries on loans previously charged-off	7	12	33	33
Net loan (charge-offs) recoveries	(6)	(13)	(1)	(22)
Provision for credit losses	18	24	86	4
Balance at end of period	$ 626	$ 513	$ 626	$ 513
As a percentage of total loans	1.27%	1.07%	1.27%	1.07%
Business loans: | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 34	$ 34	$ 40	$ 24
Provision for credit losses	(1)	2	(7)	12
Balance at end of period	33	36	33	36
Retail loans:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	80	73	80	63
Provision for credit losses	(3)	2	(2)	11
Balance at end of period	$ 77	$ 75	$ 77	$ 75
As a percentage of total loans	1.84%	1.88%	1.84%	1.88%
Retail loans: | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 70	$ 61	$ 69	$ 57
Loan charge-offs	(1)	(1)	(3)	(2)
Recoveries on loans previously charged-off	1	1	2	3
Net loan (charge-offs) recoveries	0	0	(1)	1
Provision for credit losses	(2)	2	0	5
Balance at end of period	$ 68	$ 63	$ 68	$ 63
As a percentage of total loans	1.62%	1.58%	1.62%	1.58%
Retail loans: | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 10	$ 12	$ 11	$ 6
Provision for credit losses	(1)	0	(2)	6
Balance at end of period	$ 9	$ 12	$ 9	$ 12