Fair Value (Additional Fair Value Information Related To Financial Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Financial Instruments, Financial Assets, Balance Sheet Groupings
Securities held to maturity	$ 1,605	$ 18,044
Carrying Amount
Financial Instruments, Financial Assets, Balance Sheet Groupings
Cash and due from banks	7,017	5,061
Interest-earning deposits with banks	85,173	23,413
Securities held to maturity	1,445	17,661
Net loans (excludes leases)	228,788	229,205
Other assets	3,601	5,700
Total assets	326,024	281,040
Financial Instruments, Financial Liabilities, Balance Sheet Groupings
Deposits	19,692	21,663
Borrowed funds	36,488	59,745
Unfunded loan commitments and letters of credit	584	318
Other Liabilities	413	506
Total liabilities	57,177	82,232
Fair Value
Financial Instruments, Financial Assets, Balance Sheet Groupings
Cash and due from banks	7,017	5,061
Interest-earning deposits with banks	85,173	23,413
Securities held to maturity	1,604	18,044
Net loans (excludes leases)	233,688	232,670
Other assets	3,600	5,700
Total assets	331,082	284,888
Financial Instruments, Financial Liabilities, Balance Sheet Groupings
Deposits	19,662	21,425
Borrowed funds	37,192	60,399
Unfunded loan commitments and letters of credit	584	318
Other Liabilities	413	506
Total liabilities	57,851	82,648
Fair Value | Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings
Cash and due from banks	7,017	5,061
Securities held to maturity	920	832
Total assets	7,937	5,893
Fair Value | Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings
Interest-earning deposits with banks	85,173	23,413
Securities held to maturity	489	17,039
Other assets	3,559	5,692
Total assets	89,221	46,144
Financial Instruments, Financial Liabilities, Balance Sheet Groupings
Deposits	19,662	21,425
Borrowed funds	35,571	58,622
Other Liabilities	413	506
Total liabilities	55,646	80,553
Fair Value | Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings
Securities held to maturity	195	173
Net loans (excludes leases)	233,688	232,670
Other assets	41	8
Total assets	233,924	232,851
Financial Instruments, Financial Liabilities, Balance Sheet Groupings
Borrowed funds	1,621	1,777
Unfunded loan commitments and letters of credit	584	318
Total liabilities	$ 2,205	$ 2,095