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		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Residential mortgage loans held for sale
Total principal balance	$ 41,868		$ 41,868		$ 42,726
Delinquent loans	401		401		569
Net charge-offs	1	$ 1	2	$ 3
Commercial mortgage loans held for sale
Total principal balance	39,661		39,661		39,551
Delinquent loans	4		4		$ 42
Net charge-offs	$ 3	$ 25	$ 3	$ 178