Loans, Leases, and Allowance for Credit Losses (Collateral-Dependent Loans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 47	$ 47
Recorded investment resulting from the following modification types	326	311
Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	36	18
Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	105	113
Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	6	8
Commercial | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	84	83
Commercial | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	6	5
Commercial real estate | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	16	20
Commercial real estate | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	0	2
Consumer | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	5	10
Consumer | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	0	1
Commercial and industrial | Commercial | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	64	65
Commercial and industrial | Commercial | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	1	0
Commercial and industrial | Commercial | Corporate assets, Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 27
Weighted Average LTV	55.00%
Commercial and industrial | Commercial | Single family residential, Agriculture
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost		$ 20
Weighted Average LTV		55.00%
Owner-occupied | Commercial | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	$ 20	$ 18
Owner-occupied | Commercial | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	5	5
Owner-occupied | Commercial | Office building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 11	$ 10
Weighted Average LTV	40.00%	47.00%
Term | Commercial real estate | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	$ 16	$ 20
Term | Commercial real estate | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	0	2
Term | Commercial real estate | Multi-family, Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 2	$ 12
Weighted Average LTV	28.00%	58.00%
Home equity credit line | Consumer | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	$ 1	$ 2
Home equity credit line | Consumer | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	0	0
Home equity credit line | Consumer | Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 5	$ 3
Weighted Average LTV	45.00%	34.00%
1-4 family residential | Consumer | Nonaccruing
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	$ 4	$ 8
1-4 family residential | Consumer | Nonaccruing | Interest rate below market
Financing Receivable, Allowance for Credit Losses [Line Items]
Recorded investment resulting from the following modification types	0	1
1-4 family residential | Consumer | Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 2	$ 2
Weighted Average LTV	35.00%	60.00%