Fair Value Measures - Quantitative Information about Recurring Level 3 Fair Value Financial Instruments (Details)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Assets:
Mortgage servicing rights	$ 1,031,000,000	$ 1,033,000,000
Recurring
Assets:
Mortgage servicing rights	1,031,000,000	1,033,000,000
Recurring | Rate lock commitments
Liabilities:
Rate lock commitments (net)	10,000,000	10,000,000
Significant Unobservable Inputs (Level 3) | Recurring
Assets:
Mortgage servicing rights	1,031,000,000	1,033,000,000
Significant Unobservable Inputs (Level 3) | Recurring | Valuation Technique, Discounted Cash Flow
Assets:
Mortgage servicing rights	1,031,000,000
Significant Unobservable Inputs (Level 3) | Recurring | Rate lock commitments
Liabilities:
Rate lock commitments (net)	10,000,000	$ 10,000,000
Significant Unobservable Inputs (Level 3) | Recurring | Rate lock commitments | Valuation Technique, Consensus Pricing Model
Liabilities:
Rate lock commitments (net)	$ 0
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.053
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.215
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	0.056
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	0
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.098
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	0.082
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	65
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	90
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	69
Significant Unobservable Inputs (Level 3) | Origination pull-through rate | Recurring | Rate lock commitments
Liabilities:
Rate lock commitments (net), measurement input	0.8020