Mortgage Servicing Rights - Summary of Income and Fees (Details) - Residential First Mortgage Loans $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Servicing Assets at Fair Value [Line Items]
Decreases in MSR fair value due to pay-offs, pay-downs, run-off, model changes, and other	$ (8)	[1]
Servicing Asset, Fair Value, Change in Fair Value, Valuation Input, Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Return On Mortgage Servicing Rights
Changes in fair value due to interest rate risk	$ 10	[1],[2]
Net Return (loss) on Mortgage Servicing Rights
Servicing Assets at Fair Value [Line Items]
Servicing fees, ancillary income and late fees	20	[3]
Changes in fair value due to interest rate risk	10
Loss on MSR derivatives	(16)	[4]
Total return (loss) and income on mortgage loans	6
Loan Administration Income on Mortgage Loans Subserviced
Servicing Assets at Fair Value [Line Items]
Servicing fees, ancillary income and late fees	11	[5]
Charges on subserviced custodial balances	(8)	[6]
Total return (loss) and income on mortgage loans	$ 3

[1] Changes in fair value are included within net return on mortgage servicing rights on the Consolidated Statements of Income and Comprehensive Income.

[2] Represents estimated MSR value change resulting primarily from market-driven changes which we manage through the use of derivatives.

[3] Servicing fees are recorded on an accrual basis. Ancillary income and late fees are recorded on a cash basis.

[4] Changes in the derivatives utilized as economic hedges to offset changes in fair value of the MSRs.

[5] Servicing fees are recorded on an accrual basis. Ancillary income and late fees are recorded on a cash basis.

[6] Charges on subserviced custodial balances represent interest due to MSR owner.