Fair Value - Level 3 Unobservable Inputs, Mortgage Servicing Rights - Initial Recognition (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) item	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($) item
Mortgage servicing rights
Inputs
Amount recognized | $	$ 1,718,094,000	$ 1,861,949,000	$ 1,138,045,000
Total | Mortgage servicing rights | Level 3 | Minimum
Inputs:
Annual per-loan cost of servicing | $	68	79
Total | Mortgage servicing rights | Level 3 | Maximum
Inputs:
Annual per-loan cost of servicing | $	144	197
Total | Mortgage servicing rights | Level 3 | Weighted average
Inputs:
Annual per-loan cost of servicing | $	$ 109	$ 108
Total | Mortgage servicing rights | Pricing spread | Level 3 | Minimum
Inputs:
Input	4.9	5.3
Total | Mortgage servicing rights | Pricing spread | Level 3 | Maximum
Inputs:
Input	14.3	15.5
Total | Mortgage servicing rights | Pricing spread | Level 3 | Weighted average
Inputs:
Input	6.5	7.7
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	5.0	7.9
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	17.7	26.7
Total | Mortgage servicing rights | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	7.5	10.7
Total | Mortgage servicing rights | Life | Level 3 | Minimum
Inputs:
Input	3.7	3.1
Total | Mortgage servicing rights | Life | Level 3 | Maximum
Inputs:
Input	9.3	7.7
Total | Mortgage servicing rights | Life | Level 3 | Weighted average
Inputs:
Input	8.4	6.8
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3
Inputs
Amount recognized | $	$ 1,718,094,000	$ 1,861,949,000	1,138,045,000
Unpaid principal balance of underlying loans | $	$ 83,569,657,000	$ 138,319,425,000	$ 96,571,835,000
Weighted-average servicing fee rate (as a percent)	0.44%	0.34%	0.35%
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3 | Minimum
Inputs:
Annual per-loan cost of servicing | $	$ 71	$ 80	$ 77
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Level 3 | Maximum
Inputs:
Annual per-loan cost of servicing | $	177	117	117
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 | $	$ 104	$ 103	$ 102
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Minimum
Inputs:
Input	5.5	6.0	6.8
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Maximum
Inputs:
Input	16.1	16.9	18.1
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Pricing spread | Level 3 | Weighted average
Inputs:
Input	7.8	8.8	9.4
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Minimum
Inputs:
Input	5.1	6.1	7.2
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Maximum
Inputs:
Input	23.4	31.4	49.8
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Annual total prepayment speed | Level 3 | Weighted average
Inputs:
Input	9.4	8.6	11.9
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Minimum
Inputs:
Input	3.7	3.0	1.5
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Maximum
Inputs:
Input	9.4	9.2	9.1
Total | Mortgage servicing rights | MSRs at the time of initial recognition, excluding MSR purchases | Life | Level 3 | Weighted average
Inputs:
Input	8.1	8.1	6.7