Fair Value Measurement - Quantitative Information about Recurring Level 3 Fair Value Financial Instruments (Details)	Dec. 31, 2024 USD ($) yr	Dec. 31, 2023 USD ($) yr
Assets:
Mortgage servicing rights	$ 26,000,000	$ 1,111,000,000
Fair Value	10,402,000,000	9,145,000,000
Private label collateralized mortgage obligations
Assets:
Fair Value	163,000,000	180,000,000
Recurring
Assets:
Mortgage servicing rights	26,000,000	1,111,000,000
Recurring | Private label collateralized mortgage obligations
Assets:
Fair Value	163,000,000	180,000,000
Recurring | Rate lock commitments (fallout-adjusted)
Liabilities:
Rate lock commitments (net)	3,000,000	3,000,000
Significant Unobservable Inputs (Level 3) | Recurring
Assets:
Mortgage servicing rights	26,000,000	1,111,000,000
Significant Unobservable Inputs (Level 3) | Recurring | Private label collateralized mortgage obligations
Assets:
Fair Value	33,000,000	32,000,000
Significant Unobservable Inputs (Level 3) | Recurring | Rate lock commitments (fallout-adjusted)
Liabilities:
Rate lock commitments (net)	$ 3,000,000	$ 3,000,000
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.008	0.050
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.164	0.217
Significant Unobservable Inputs (Level 3) | Option adjusted spread | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	0.021	0.054
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.000	0.000
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	0.117	0.100
Significant Unobservable Inputs (Level 3) | Constant prepayment rate | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	0.094	0.079
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Minimum | Recurring
Assets:
Mortgage servicing rights, measurement input	65	65
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Maximum | Recurring
Assets:
Mortgage servicing rights, measurement input	90	90
Significant Unobservable Inputs (Level 3) | Weighted average cost to service per loan | Weighted average | Recurring
Assets:
Mortgage servicing rights, measurement input	71	69
Significant Unobservable Inputs (Level 3) | Constant default rates | Minimum | Recurring | Private label collateralized mortgage obligations
Assets:
Fair value, measurement input	0.0010	0.0010
Significant Unobservable Inputs (Level 3) | Constant default rates | Maximum | Recurring | Private label collateralized mortgage obligations
Assets:
Fair value, measurement input	0.0020	0.0030
Significant Unobservable Inputs (Level 3) | Weighted average life | Minimum | Recurring | Private label collateralized mortgage obligations
Assets:
Fair value, measurement input | yr	0.055	0.082
Significant Unobservable Inputs (Level 3) | Weighted average life | Maximum | Recurring | Private label collateralized mortgage obligations
Assets:
Fair value, measurement input | yr	0.122	0.118
Significant Unobservable Inputs (Level 3) | Origination pull-through rate | Recurring | Rate lock commitments (fallout-adjusted)
Liabilities:
Rate lock commitments (net), measurement input	0.5040	64.3
Significant Unobservable Inputs (Level 3) | Rate lock commitments (fallout-adjusted) | Recurring | Rate lock commitments (fallout-adjusted)
Liabilities:
Rate lock commitments (net)	$ 0	$ 9,000,000