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		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 728	$ 693	$ 728	$ 661	$ 661
Provision for credit losses	0	33	14	63
Balance at end of period	$ 717	$ 728	$ 717	$ 728	728
As a percentage of total loans	1.38%	1.31%	1.38%	1.31%
Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 691	$ 641	$ 688	$ 610	610
Loan charge-offs	(28)	(11)	(49)	(23)
Recoveries on loans previously charged-off	17	13	24	27
Net loan (charge-offs) recoveries	(11)	2	(25)	4
Provision for credit losses	6	41	23	70
Balance at end of period	$ 686	$ 684	$ 686	$ 684	688
As a percentage of total loans	1.32%	1.23%	1.32%	1.23%
Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 37	$ 52	$ 40	$ 51	51
Provision for credit losses	(6)	(8)	(9)	(7)
Balance at end of period	31	44	31	44	40
Business loans:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	654	609	651	581	581
Provision for credit losses	1	36	18	62
Balance at end of period	$ 643	$ 648	$ 643	$ 648	651
As a percentage of total loans	1.35%	1.26%	1.35%	1.26%
Business loans: | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 626	$ 570	$ 620	$ 541	541
Loan charge-offs	(28)	(10)	(48)	(21)
Recoveries on loans previously charged-off	16	13	22	26
Net loan (charge-offs) recoveries	(12)	3	(26)	5
Provision for credit losses	6	41	26	68
Balance at end of period	$ 620	$ 614	$ 620	$ 614	620
As a percentage of total loans	1.30%	1.19%	1.30%	1.19%
Business loans: | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 28	$ 39	$ 31	$ 40	40
Provision for credit losses	(5)	(5)	(8)	(6)
Balance at end of period	23	34	23	34	31
Retail loans:
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	74	84	77	80	80
Provision for credit losses	(1)	(3)	(4)	1
Balance at end of period	$ 74	$ 80	$ 74	$ 80	77
As a percentage of total loans	1.79%	1.95%	1.79%	1.95%
Retail loans: | Financing Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 65	$ 71	$ 68	$ 69	69
Loan charge-offs	0	(1)	(1)	(2)
Recoveries on loans previously charged-off	1	0	2	1
Net loan (charge-offs) recoveries	1	(1)	1	(1)
Provision for credit losses	0	0	(3)	2
Balance at end of period	$ 66	$ 70	$ 66	$ 70	68
As a percentage of total loans	1.59%	1.70%	1.59%	1.70%
Retail loans: | Unused Commitments to Extend Credit
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 9	$ 13	$ 9	$ 11	11
Provision for credit losses	(1)	(3)	(1)	(1)
Balance at end of period	$ 8	$ 10	$ 8	$ 10	$ 9