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, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 609	$ 683	$ 618	$ 992
Provision for credit losses	28	(42)	27	(359)
Balance at end of period	$ 624	$ 639	$ 624	$ 639
As a percentage of total loans	1.21%	1.33%	1.21%	1.33%
Financing Receivable
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 563	$ 652	$ 588	$ 948
Loan charge-offs	(26)	(26)	(57)	(50)
Recoveries on loans previously charged-off	13	24	36	56
Net loan (charge-offs) recoveries	(13)	(2)	(21)	6
Provision for credit losses	26	(41)	9	(345)
Balance at end of period	$ 576	$ 609	$ 576	$ 609
As a percentage of total loans	1.11%	1.26%	1.11%	1.26%
Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 46	$ 31	$ 30	$ 44
Provision for credit losses	2	(1)	18	(14)
Balance at end of period	48	30	48	30
Business loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	536	613	555	930
Provision for credit losses	26	(31)	16	(357)
Balance at end of period	$ 549	$ 578	$ 549	$ 578
As a percentage of total loans	1.15%	1.30%	1.15%	1.30%
Business loans | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 502	$ 589	$ 531	$ 895
Loan charge-offs	(25)	(26)	(55)	(48)
Recoveries on loans previously charged-off	12	22	33	53
Net loan (charge-offs) recoveries	(13)	(4)	(22)	5
Provision for credit losses	24	(31)	4	(346)
Balance at end of period	$ 513	$ 554	$ 513	$ 554
As a percentage of total loans	1.07%	1.25%	1.07%	1.25%
Business loans | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 34	$ 24	$ 24	$ 35
Provision for credit losses	2	0	12	(11)
Balance at end of period	36	24	36	24
Retail loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	73	70	63	62
Provision for credit losses	2	(11)	11	(2)
Balance at end of period	$ 75	$ 61	$ 75	$ 61
As a percentage of total loans	1.88%	1.57%	1.88%	1.57%
Retail loans | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 61	$ 63	$ 57	$ 53
Loan charge-offs	(1)	0	(2)	(2)
Recoveries on loans previously charged-off	1	2	3	3
Net loan (charge-offs) recoveries	0	2	1	1
Provision for credit losses	2	(10)	5	1
Balance at end of period	$ 63	$ 55	$ 63	$ 55
As a percentage of total loans	1.58%	1.42%	1.58%	1.42%
Retail loans | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance at beginning of period	$ 12	$ 7	$ 6	$ 9
Provision for credit losses	0	(1)	6	(3)
Balance at end of period	$ 12	$ 6	$ 12	$ 6