Commitments and Contingencies (Commitments to Extend/Purchase) (Details) - Residential Real Estate [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 4,155	$ 5,025
Home Equity Lines of Credit, Pledged Asset Lines, and Other Lines of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commitments to extend credit related to unused HELOCs, PALs, and other lines of credit	3,674	4,533
First Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commitments to purchase First Mortgage loans	$ 481	$ 492