Fair Value (Schedule of Assets and Liabilities Measured at Fair Value by Class on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
ASSETS
Investment securities, available-for-sale	$ 11,594	$ 11,915
Trading securities	12	465
Total assets	12,734	13,525
LIABILITIES
Securities sold, not yet purchased	281	187
Total liabilities	634	638
U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	10,123	10,208
Municipal securities
ASSETS
Investment securities, available-for-sale	1,447	1,634
Other debt securities
ASSETS
Investment securities, available-for-sale	24	73
Bank-owned life insurance
ASSETS
Other noninterest-bearing investments	547	546
Private equity investments
ASSETS
Other noninterest-bearing investments	85	85
Agriculture loan servicing and interest-only strips
ASSETS
Other assets	18	14
Derivatives
ASSETS
Other assets	369	386
LIABILITIES
Other liabilities	353	451
Level 1
ASSETS
Investment securities, available-for-sale	511	393
Trading securities		395
Total assets	623	906
LIABILITIES
Securities sold, not yet purchased	281	187
Total liabilities	281	187
Level 1 | U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	511	393
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	3	4
Level 1 | Agriculture loan servicing and interest-only strips
ASSETS
Other assets
Level 1 | Derivatives
ASSETS
Other assets
LIABILITIES
Other liabilities
Level 2
ASSETS
Investment securities, available-for-sale	11,083	11,522
Trading securities	12	70
Total assets	12,011	12,524
LIABILITIES
Securities sold, not yet purchased	0	0
Total liabilities	353	451
Level 2 | U.S. Treasury, agencies and corporations
ASSETS
Investment securities, available-for-sale	9,612	9,815
Level 2 | Municipal securities
ASSETS
Investment securities, available-for-sale	1,447	1,634
Level 2 | Other debt securities
ASSETS
Investment securities, available-for-sale	24	73
Level 2 | Bank-owned life insurance
ASSETS
Other noninterest-bearing investments	547	546
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
ASSETS
Other assets	369	386
LIABILITIES
Other liabilities	353	451
Level 3
ASSETS
Investment securities, available-for-sale	0	0
Trading securities
Total assets	100	95
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	82	81
Level 3 | Agriculture loan servicing and interest-only strips
ASSETS
Other assets	18	14
Level 3 | Derivatives
ASSETS
Other assets
LIABILITIES
Other liabilities
Deferred compensation plan assets | Deferred compensation plan assets
ASSETS
Other assets	109	114
Deferred compensation plan assets | Level 1 | Deferred compensation plan assets
ASSETS
Other assets	109	114
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