Fair Value - Level 3 Unobservable Inputs, Mortgage Servicing Rights - Initial Recognition (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) Y item	Dec. 31, 2023 USD ($) Y	Dec. 31, 2022 USD ($) Y
Mortgage servicing rights
Inputs
Amount recognized	$ 2,280,830,000	$ 1,849,957,000	$ 1,718,094,000
Total | Mortgage servicing rights | Level 3 | Minimum
Inputs:
Annual per-loan cost of servicing	68	70
Total | Mortgage servicing rights | Level 3 | Maximum
Inputs:
Annual per-loan cost of servicing	130	135
Total | Mortgage servicing rights | Level 3 | Weighted average
Inputs:
Annual per-loan cost of servicing	$ 105	$ 107
Total | Mortgage servicing rights | Pricing spread | Level 3 | Minimum
Inputs:
Input	0.05	0.055
Total | Mortgage servicing rights | Pricing spread | Level 3 | Maximum
Inputs:
Input	0.113	0.126
Total | Mortgage servicing rights | Pricing spread | Level 3 | Weighted average
Inputs:
Input	0.062	0.064
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	0.059	0.061
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	0.177	0.178
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	0.078	0.083
Total | Mortgage servicing rights | Life | Level 3 | Minimum
Inputs:
Input | Y	2.7	3
Total | Mortgage servicing rights | Life | Level 3 | Maximum
Inputs:
Input | Y	9.1	9
Total | Mortgage servicing rights | Life | Level 3 | Weighted average
Inputs:
Input | Y	8.4	8.1
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3
Inputs
Amount recognized	$ 2,280,830,000	$ 1,849,957,000	1,718,094,000
Unpaid principal balance of underlying loans	$ 100,662,790,000	$ 86,606,196,000	$ 83,569,657,000
Weighted-average servicing fee rate (as a percent)	0.45%	0.46%	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	$ 69	$ 68	$ 71
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	177
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	$ 99	$ 99	$ 104
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Minimum
Inputs:
Input	4.9	0.055	0.055
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	0.161
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Weighted average
Inputs:
Input	0.058	0.068	0.078
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	0.064	0.072	0.051
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	0.258	0.232	0.234
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	0.101	0.107	0.094
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Minimum
Inputs:
Input | Y	3.5	3	3.7
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Maximum
Inputs:
Input | Y	9.9	9.8	9.4
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Weighted average
Inputs:
Input | Y	8	7.7	8.1