Fair Value - Level 3 Unobservable Inputs, Mortgage Servicing Rights - Initial Recognition (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025 USD ($) Y	Jun. 30, 2024 USD ($) Y	Jun. 30, 2025 USD ($) Y	Jun. 30, 2024 USD ($) Y	Dec. 31, 2024 USD ($) Y
Mortgage servicing rights
Inputs
Amount recognized	$ 814,538,000	$ 541,207,000	$ 1,464,887,000	$ 953,727,000
Total | Mortgage servicing rights | Level 3 | Minimum
Inputs:
Annual per-loan cost of servicing			68		$ 68
Total | Mortgage servicing rights | Level 3 | Maximum
Inputs:
Annual per-loan cost of servicing			127		130
Total | Mortgage servicing rights | Level 3 | Weighted average
Inputs:
Annual per-loan cost of servicing			$ 105		$ 105
Total | Mortgage servicing rights | Pricing spread | Level 3 | Minimum
Inputs:
Input	0.049		0.049		0.05
Total | Mortgage servicing rights | Pricing spread | Level 3 | Maximum
Inputs:
Input	0.114		0.114		0.113
Total | Mortgage servicing rights | Pricing spread | Level 3 | Weighted average
Inputs:
Input	0.06		0.06		0.062
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	0.062		0.062		0.059
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	0.19		0.19		0.177
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	0.089		0.089		0.078
Total | Mortgage servicing rights | Life | Level 3 | Minimum
Inputs:
Input | Y	2.6		2.6		2.7
Total | Mortgage servicing rights | Life | Level 3 | Maximum
Inputs:
Input | Y	8.8		8.8		9.1
Total | Mortgage servicing rights | Life | Level 3 | Weighted average
Inputs:
Input | Y	8.1		8.1		8.4
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3
Inputs
Amount recognized	$ 814,538,000	541,207,000	$ 1,464,887,000	953,727,000
Unpaid principal balance of underlying loans	$ 34,697,004,000	$ 24,741,715,000	$ 62,361,980,000	$ 44,226,530,000
Weighted-average servicing fee rate (as a percent)	0.43%	0.43%	0.43%	0.44%
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3 | Minimum
Inputs:
Annual per-loan cost of servicing	$ 70	$ 70	$ 70	$ 70
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3 | Maximum
Inputs:
Annual per-loan cost of servicing	127	127	127	127
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3 | Weighted average
Inputs:
Annual per-loan cost of servicing	$ 100	$ 98	$ 100	$ 98
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Minimum
Inputs:
Input	0.049	0.053	0.049	0.053
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Maximum
Inputs:
Input	0.126	0.126	0.126	0.126
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Weighted average
Inputs:
Input	0.055	0.06	0.055	0.061
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	0.067	0.073	0.066	0.073
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	0.155	0.15	0.155	0.159
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	0.086	0.10	0.087	0.105
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Minimum
Inputs:
Input	3.8	3.5	3.8	3.5
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Maximum
Inputs:
Input	10.1	9.7	10.2	9.7
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Weighted average
Inputs:
Input | Y	8.8	7.9	8.7	7.7