Fair Value (Schedule of Assets and Liabilities Measured at Fair Value by Class on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
ASSETS
Investment securities, available-for-sale	$ 25,297	$ 24,048
Trading account	304	372
Total assets	26,509	25,427
LIABILITIES
Securities sold, not yet purchased	222	254
Total liabilities	517	305
U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	23,486	22,278
Municipal securities
ASSETS
Investment securities, available-for-sale	1,737	1,694
Other debt securities
ASSETS
Investment securities, available-for-sale	74	76
Bank-owned life insurance
ASSETS
Other noninterest-bearing investments	541	537
Private equity investments
ASSETS
Other noninterest-bearing investments	86	101
Agriculture loan servicing and interest-only strips
ASSETS
Other assets	12	12
Derivatives | Derivatives designated as hedges
ASSETS
Other assets	58	10
Derivatives | Derivatives not designated as hedging instruments
ASSETS
Other assets	94	209
LIABILITIES
Other liabilities	293	51
Derivatives designated as hedges
LIABILITIES
Other liabilities	2
Level 1
ASSETS
Investment securities, available-for-sale	442	134
Trading account	14	14
Total assets	582	321
LIABILITIES
Securities sold, not yet purchased	222	254
Total liabilities	222	254
Level 1 | U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	442	134
Level 1 | Municipal securities
ASSETS
Investment securities, available-for-sale
Level 1 | Other debt securities
ASSETS
Investment securities, available-for-sale
Level 1 | Bank-owned life insurance
ASSETS
Other noninterest-bearing investments
Level 1 | Private equity investments
ASSETS
Other noninterest-bearing investments	9	35
Level 1 | Agriculture loan servicing and interest-only strips
ASSETS
Other assets
Level 1 | Derivatives | Derivatives designated as hedges
ASSETS
Other assets
Level 1 | Derivatives | Derivatives not designated as hedging instruments
ASSETS
Other assets
LIABILITIES
Other liabilities
Level 1 | Derivatives designated as hedges
LIABILITIES
Other liabilities
Level 2
ASSETS
Investment securities, available-for-sale	24,855	23,914
Trading account	290	358
Total assets	25,838	25,028
LIABILITIES
Securities sold, not yet purchased	0	0
Total liabilities	295	51
Level 2 | U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	23,044	22,144
Level 2 | Municipal securities
ASSETS
Investment securities, available-for-sale	1,737	1,694
Level 2 | Other debt securities
ASSETS
Investment securities, available-for-sale	74	76
Level 2 | Bank-owned life insurance
ASSETS
Other noninterest-bearing investments	541	537
Level 2 | Private equity investments
ASSETS
Other noninterest-bearing investments
Level 2 | Agriculture loan servicing and interest-only strips
ASSETS
Other assets
Level 2 | Derivatives | Derivatives designated as hedges
ASSETS
Other assets	58	10
Level 2 | Derivatives | Derivatives not designated as hedging instruments
ASSETS
Other assets	94	209
LIABILITIES
Other liabilities	293	51
Level 2 | Derivatives designated as hedges
LIABILITIES
Other liabilities	2
Level 3
ASSETS
Investment securities, available-for-sale	0	0
Trading account
Total assets	89	78
LIABILITIES
Securities sold, not yet purchased	0	0
Total liabilities	0	0
Level 3 | U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	0	0
Level 3 | Municipal securities
ASSETS
Investment securities, available-for-sale
Level 3 | Other debt securities
ASSETS
Investment securities, available-for-sale
Level 3 | Bank-owned life insurance
ASSETS
Other noninterest-bearing investments
Level 3 | Private equity investments
ASSETS
Other noninterest-bearing investments	77	66
Level 3 | Agriculture loan servicing and interest-only strips
ASSETS
Other assets	12	12
Level 3 | Derivatives | Derivatives designated as hedges
ASSETS
Other assets
Level 3 | Derivatives | Derivatives not designated as hedging instruments
ASSETS
Other assets
LIABILITIES
Other liabilities
Level 3 | Derivatives designated as hedges
LIABILITIES
Other liabilities
Deferred compensation plan assets | Deferred compensation plan assets
ASSETS
Other assets	117	138
Deferred compensation plan assets | Level 1 | Deferred compensation plan assets
ASSETS
Other assets	117	138
Deferred compensation plan assets | Level 2 | Deferred compensation plan assets
ASSETS
Other assets
Deferred compensation plan assets | Level 3 | Deferred compensation plan assets
ASSETS
Other assets