Mortgage Servicing Rights - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Transfers and Servicing [Abstract]
Other real estate owned	$ 3,800		$ 3,800		$ 3,800
Contractually specified servicing fee, late fee, and ancillary fee earned in exchange for servicing financial asset	$ 3	$ 2	$ 5	$ 4
Fixed Rate Conventional Loans
Servicing Asset Key Economic Assumptions [Line Items]
Risk premium on 10-year U.S. Treasury	0.0700		0.0700
Loans Excluding Fixed Rate Conventional Loans
Servicing Asset Key Economic Assumptions [Line Items]
Risk premium on 10-year U.S. Treasury	0.0800		0.0800