Capitalized Servicing Assets - Changes in Capitalized Servicing Assets (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Residential Mortgage Loans [Member]
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	$ 194	$ 241	$ 231
Originations	13	7	66
Purchases	350
Acquired in business combination		12
Amortization	(101)	(66)	(56)
Amortized value, ending balance	456	194	241
Valuation allowance			(24)
Ending balance, net	456	194	217
Total loans serviced for others	155,342	118,392
Residential Mortgage Loans [Member] \| Loans Serviced for Others [Member]
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	40,021	22,365
Residential Mortgage Loans [Member] \| Loans Sub-serviced for Others [Member]
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	115,321	96,027
Commercial Mortgage Loans [Member]
Servicing Asset at Amortized Cost [Line Items]
Amortized value, Beginning balance	126	133	134
Originations	27	24	33
Amortization	(30)	(31)	(34)
Amortized value, ending balance	123	126	133
Ending balance, net	123	126	$ 133
Total loans serviced for others	28,030	26,007
Commercial Mortgage Loans [Member] \| Loans Serviced for Others [Member]
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	24,157	22,166
Commercial Mortgage Loans [Member] \| Loans Sub-serviced for Others [Member]
Servicing Asset at Amortized Cost [Line Items]
Total loans serviced for others	$ 3,873	$ 3,841

Mortgage loans serviced for others.

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- Definition

Service asset at amortized value, acquired in business combination.

+ References

No definition available.

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- Definition

Amount of contract to service financial assets originated during the period, under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

No definition available.

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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.

+ References

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- Definition

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
-Topic 860
-SubTopic 50
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-Paragraph 4
-Subparagraph (a)(2)
-Publisher FASB
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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.

+ References

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- Definition

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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- Definition

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.

+ References

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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.

+ References

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