v3.22.0.1
Fair Value Measurements (Summary Of Quantitative Information About Level 3 Fair Value Measurements) (Details) - Discounted Cash Flow [Member]
$ in Millions
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Mortgage Servicing Rights [Member] | Level 3 [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Assets, Fair Value Disclosure $ 418 $ 296 $ 345
Commercial Mortgage Loans Held For Sale | Level 3 [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Assets, Fair Value Disclosure $ 90    
Recurring Fair Value Measurements [Member] | Mortgage Servicing Rights [Member] | Minimum [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Weighted Average CPR 0.072 0.081 0.074
Option-Adjusted Spread 3.70% 4.80% 5.20%
Recurring Fair Value Measurements [Member] | Mortgage Servicing Rights [Member] | Maximum [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Weighted Average CPR 0.222 0.312 0.261
Option-Adjusted Spread 7.70% 9.50% 10.20%
Recurring Fair Value Measurements [Member] | Mortgage Servicing Rights [Member] | Weighted Average [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Weighted Average CPR 0.105 0.156 0.120
Option-Adjusted Spread 4.50% 5.60% 6.20%
Recurring Fair Value Measurements [Member] | Commercial Mortgage Loans Held For Sale | Minimum [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Loans Held-for-sale, Measurement Input 0.002    
Recurring Fair Value Measurements [Member] | Commercial Mortgage Loans Held For Sale | Maximum [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Loans Held-for-sale, Measurement Input 0.194    
Recurring Fair Value Measurements [Member] | Commercial Mortgage Loans Held For Sale | Weighted Average [Member]      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Loans Held-for-sale, Measurement Input 0.013