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		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Residential mortgage loans held for sale
Total principal balance	$ 41,413		$ 41,413		$ 42,726
Delinquent loans	354		354		569
Net charge-offs	1	$ 1	3	$ 4
Commercial mortgage loans held for sale
Total principal balance	38,457		38,457		39,551
Delinquent loans	1		1		$ 42
Net charge-offs	$ 9	$ 2	$ 12	$ 180