Fair Value (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Assets
Investment securities – available for sale	$ 51,188	$ 41,785
Mortgage servicing rights	3,739	3,686
Financial derivatives	660	897
Liabilities
Financial derivatives	3,706	3,538
Other liabilities	100	$ 100
Unrealized gain on Visa C shares	$ 244
Assets At Fair Value | Assets, Total | Assets
Liabilities
Concentration risk, percentage	12.00%	10.00%
Level 3 Assets | Assets, Total | Assets
Liabilities
Concentration risk, percentage	11.00%	13.00%
Level 3 Assets | Assets | Assets
Liabilities
Concentration risk, percentage	1.00%	1.00%
Liabilities At Fair Value | Liabilities, Total | Liability
Liabilities
Concentration risk, percentage	1.00%	1.00%
Level Three Liabilities | Liabilities, Total | Liability
Liabilities
Concentration risk, percentage	5.00%	6.00%
Level Three Liabilities | Liability | Liability
Liabilities
Concentration risk, percentage	1.00%	1.00%
Fair Value, Recurring
Assets
Investment securities – available for sale	$ 51,188	$ 41,785
Loans	1,191	1,238
Equity investments	3,203	2,717
Trading securities	2,350	2,799
Financial derivatives	3,120	3,429
Other assets	568	496
Total Assets	66,296	56,862
Liabilities
Other borrowed funds	791	817
Financial derivatives	6,216	5,899
Other liabilities	194	237
Total liabilities	7,201	6,953
Level 1 | Fair Value, Recurring
Assets
Investment securities – available for sale	15,513	6,292
Equity investments	972	574
Trading securities	515	377
Financial derivatives	5	29
Other assets	431	403
Total Assets	17,436	7,675
Liabilities
Other borrowed funds	661	724
Financial derivatives	6	11
Total liabilities	667	735
Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	34,798	34,537
Loans	490	512
Trading securities	1,835	2,422
Financial derivatives	3,103	3,394
Other assets	129	85
Total Assets	41,193	41,548
Liabilities
Other borrowed funds	121	84
Financial derivatives	6,027	5,736
Total liabilities	6,148	5,820
Level 3
Assets
Commercial mortgage loans held for sale	4	11
Equity investments	2,030	1,952
Liabilities
Financial derivatives	180	145
Level 3 | Fair Value, Recurring
Assets
Investment securities – available for sale	877	956
Loans	701	726
Equity investments	2,030	1,952
Financial derivatives	12	6
Other assets	8	8
Total Assets	7,466	7,448
Liabilities
Other borrowed funds	9	9
Financial derivatives	183	152
Other liabilities	194	237
Total liabilities	386	398
Residential mortgage loans held for sale | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	642	474
Residential mortgage loans held for sale | Level 2 | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	547	371
Residential mortgage loans held for sale | Level 3 | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	95	103
Commercial mortgage loans held for sale | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	295	238
Commercial mortgage loans held for sale | Level 2 | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	291	227
Commercial mortgage loans held for sale | Level 3 | Fair Value, Recurring
Assets
Commercial mortgage loans held for sale	4	11
U.S. Treasury and government agencies | Fair Value, Recurring
Assets
Investment securities – available for sale	16,474	6,951
U.S. Treasury and government agencies | Level 1 | Fair Value, Recurring
Assets
Investment securities – available for sale	15,513	6,292
U.S. Treasury and government agencies | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	961	659
Residential mortgage-backed | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	27,096	27,880
Residential mortgage-backed | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	624	696
Residential mortgage-backed | Level 2 | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	27,096	27,880
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	624	696
Commercial mortgage servicing rights | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	1,617	1,546
Commercial mortgage servicing rights | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	797	869
Commercial mortgage servicing rights | Level 2 | Mortgage-backed Securities Agency | Fair Value, Recurring
Assets
Investment securities – available for sale	1,617	1,546
Commercial mortgage servicing rights | Level 2 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	694	766
Commercial mortgage servicing rights | Level 3 | Mortgage-backed Securities Non-agency | Fair Value, Recurring
Assets
Investment securities – available for sale	103	103
Asset-backed | Fair Value, Recurring
Assets
Investment securities – available for sale	2,120	1,116
Asset-backed | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	2,024	1,014
Asset-backed | Level 3 | Fair Value, Recurring
Assets
Investment securities – available for sale	96	102
Other | Fair Value, Recurring
Assets
Investment securities – available for sale	2,460	2,727
Other | Level 2 | Fair Value, Recurring
Assets
Investment securities – available for sale	2,406	2,672
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	2,657	2,654
Residential mortgage servicing rights | Level 3 | Fair Value, Recurring
Assets
Mortgage servicing rights	2,657	2,654
Commercial mortgage servicing rights | Fair Value, Recurring
Assets
Mortgage servicing rights	1,082	1,032
Commercial mortgage servicing rights | Level 3 | Fair Value, Recurring
Assets
Mortgage servicing rights	$ 1,082	$ 1,032