Capitalized Servicing Assets - Changes in Capitalized Servicing Assets (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Residential Mortgage Loans
Servicing Asset at Amortized Cost [Line Items]
Beginning balance	$ 456	$ 194	$ 241
Originations	20	13	7
Purchases	0	350	0
Acquired in business combination	0	0	12
Amortization	(108)	(101)	(66)
Ending balance	368	456	194
Valuation allowance	0	0	0
Ending balance, net	368	456	194
Total loans serviced for others	149,649	155,342
Residential Mortgage Loans \| Loans serviced for others
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	38,105	40,021
Residential Mortgage Loans \| Loans sub-serviced for others
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	111,544	115,321
Commercial Mortgage Loans
Servicing Asset at Amortized Cost [Line Items]
Beginning balance	123	126	133
Originations	34	27	24
Purchases	0	0	0
Acquired in business combination	0	0	0
Amortization	(31)	(30)	(31)
Ending balance	126	123	126
Valuation allowance	0	0	0
Ending balance, net	126	123	$ 126
Total loans serviced for others	31,537	28,030
Commercial Mortgage Loans \| Loans serviced for others
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	27,474	24,157
Commercial Mortgage Loans \| Loans sub-serviced for others
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	$ 4,063	$ 3,873

Mortgage Loans Serviced For Others

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Service Asset At Amortized Value Acquired In Business Combination

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- Definition

Servicing Asset At Amortized Value Originations

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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

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Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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