Loan Sale and Servicing Activities and Variable Interest Entities (Principal Balance, Delinquent Loans (Loans 90 Days or More Past Due), and Net Charge-Offs Related to Serviced Loans) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Residential mortgage loans held for sale
Total principal balance	$ 40,451		$ 41,031
Delinquent loans	322		346
Net charge-offs	2	$ 1
Commercial mortgage loans held for sale
Total principal balance	58,186		57,974
Delinquent loans
Net charge-offs	$ 4