Fair Value (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Assets
Investment securities – available for sale	$ 41,787	$ 44,159
Mortgage servicing rights	3,455	3,423
Financial derivatives	783	1,531
Liabilities
Financial derivatives	$ 4,565	$ 4,524
Assets At Fair Value | Assets, Total | Assets
Liabilities
Concentration risk, percentage	10.00%	11.00%
Level 3 Assets | Assets, Total | Assets
Liabilities
Concentration risk, percentage	12.00%	12.00%
Level 3 Assets | Assets | Assets
Liabilities
Concentration risk, percentage	1.00%	1.00%
Liabilities At Fair Value | Liabilities, Total | Liability
Liabilities
Concentration risk, percentage	2.00%	2.00%
Level Three Liabilities | Liabilities, Total | Liability
Liabilities
Concentration risk, percentage	5.00%	4.00%
Level Three Liabilities | Liability | Liability
Liabilities
Concentration risk, percentage	1.00%	1.00%
Fair Value, Recurring
Assets
Investment securities – available for sale	$ 41,787	$ 44,159
Loans	1,259	1,310
Equity investments	2,610	3,147
Trading securities	2,569	1,966
Financial derivatives	3,220	3,768
Other assets	452	432
Total Assets	56,102	59,135
Liabilities
Other borrowed funds	1,244	1,466
Financial derivatives	7,003	7,618
Other liabilities	239	294
Total liabilities	8,486	9,378
Level 1 | Fair Value, Recurring
Assets
Investment securities – available for sale	6,874	8,108
Equity investments	807	1,173
Trading securities	570	798
Financial derivatives	2	16
Other assets	387	352
Total Assets	8,640	10,447
Liabilities
Other borrowed funds	1,139	1,230
Financial derivatives	1	4
Total liabilities	1,140	1,234
Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	33,971	35,050
Loans	514	541
Trading securities	1,999	1,168
Financial derivatives	3,212	3,747
Other assets	65	80
Total Assets	40,295	41,240
Liabilities
Other borrowed funds	100	232
Financial derivatives	6,862	7,491
Total liabilities	6,962	7,723
Level 3 | Fair Value, Recurring
Assets
Investment securities – available for sale	942	1,001
Loans	745	769
Equity investments	1,623	1,778
Financial derivatives	6	5
Total Assets	6,987	7,252
Liabilities
Other borrowed funds	5	4
Financial derivatives	140	123
Other liabilities	239	294
Total liabilities	384	421
Residential mortgage loans held for sale | Fair Value, Recurring
Assets
Loans held for sale	686	654
Residential mortgage loans held for sale | Level 2 | Fair Value, Recurring
Assets
Loans held for sale	495	411
Residential mortgage loans held for sale | Level 3 | Fair Value, Recurring
Assets
Loans held for sale	191	243
Commercial mortgage loans held for sale | Fair Value, Recurring
Assets
Loans held for sale	64	276
Commercial mortgage loans held for sale | Level 2 | Fair Value, Recurring
Assets
Loans held for sale	39	243
Commercial mortgage loans held for sale | Level 3 | Fair Value, Recurring
Assets
Loans held for sale	25	33
U.S. Treasury and government agencies | Fair Value, Recurring
Assets
Investment securities – available for sale	7,110	8,370
U.S. Treasury and government agencies | Level 1 | Fair Value, Recurring
Assets
Investment securities – available for sale	6,874	8,108
U.S. Treasury and government agencies | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	236	262
Residential mortgage-backed | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	27,655	28,823
Residential mortgage-backed | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	768	819
Residential mortgage-backed | Level 2 | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	27,655	28,823
Residential mortgage-backed | Level 2 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale
Residential mortgage-backed | Level 3 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	768	819
Commercial mortgage-backed | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	1,593	1,675
Commercial mortgage-backed | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	947	1,256
Commercial mortgage-backed | Level 2 | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	1,593	1,675
Commercial mortgage-backed | Level 2 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	944	1,253
Commercial mortgage-backed | Level 3 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	3	3
Asset-backed | Fair Value, Recurring
Assets
Investment securities – available for sale	934	129
Asset-backed | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	817	5
Asset-backed | Level 3 | Fair Value, Recurring
Assets
Investment securities – available for sale	117	124
Other | Fair Value, Recurring
Assets
Investment securities – available for sale	2,780	3,087
Other | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	2,726	3,032
Other | Level 3 | Fair Value, Recurring
Assets
Investment securities – available for sale	54	55
Residential mortgage servicing rights | Fair Value, Recurring
Assets
Mortgage servicing rights	2,349	2,310
Residential mortgage servicing rights | Level 3 | Fair Value, Recurring
Assets
Mortgage servicing rights	2,349	2,310
Commercial mortgage servicing rights | Fair Value, Recurring
Assets
Mortgage servicing rights	1,106	1,113
Commercial mortgage servicing rights | Level 3 | Fair Value, Recurring
Assets
Mortgage servicing rights	$ 1,106	$ 1,113