Loans, Lending Commitments and Related Allowance for Credit Losses - Allowance for Credit Losses Rollforward - Loans and Lending Commitments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Allowance for loan losses rollforward
Beginning balance			$ 1,066	$ 1,169
Gross charge-offs			(126)	(155)
Recoveries			21	7
Net (charge-offs)/ recoveries			(105)	(148)
Provision (release)	$ 6	$ 18	225	81
Other			27	2
Ending balance	$ 1,213	$ 1,104	$ 1,213	$ 1,104
Percent of loans to total loans	100.00%	100.00%	100.00%	100.00%
Allowance for lending commitments rollforward
Beginning balance			$ 656	$ 551
Provision (release)	$ (6)	$ 61	106	68
Other			22	0
Ending balance	784	619	784	619
Total ending balance	1,997	1,723	1,997	1,723
Corporate
Allowance for loan losses rollforward
Beginning balance			200	241
Gross charge-offs			(10)	(39)
Recoveries			0	0
Net (charge-offs)/ recoveries			(10)	(39)
Provision (release)			41	24
Other			8	1
Ending balance	$ 239	$ 227	$ 239	$ 227
Percent of loans to total loans	3.00%	3.00%	3.00%	3.00%
Allowance for lending commitments rollforward
Beginning balance			$ 507	$ 431
Provision (release)			93	41
Other			17	(1)
Ending balance	$ 617	$ 471	617	471
Total ending balance	856	698	856	698
Secured lending facilities
Allowance for loan losses rollforward
Beginning balance			140	153
Gross charge-offs			0	(11)
Recoveries			0	0
Net (charge-offs)/ recoveries			0	(11)
Provision (release)			55	(12)
Other			5	0
Ending balance	$ 200	$ 130	$ 200	$ 130
Percent of loans to total loans	25.00%	21.00%	25.00%	21.00%
Allowance for lending commitments rollforward
Beginning balance			$ 88	$ 70
Provision (release)			39	19
Other			4	1
Ending balance	$ 131	$ 90	131	90
Total ending balance	331	220	331	220
Commercial real estate
Allowance for loan losses rollforward
Beginning balance			373	463
Gross charge-offs			(99)	(103)
Recoveries			21	4
Net (charge-offs)/ recoveries			(78)	(99)
Provision (release)			55	44
Other			14	3
Ending balance	$ 364	$ 411	$ 364	$ 411
Percent of loans to total loans	3.00%	4.00%	3.00%	4.00%
Allowance for lending commitments rollforward
Beginning balance			$ 40	$ 26
Provision (release)			(25)	9
Other			0	0
Ending balance	$ 15	$ 35	15	35
Total ending balance	379	446	379	446
Residential real estate
Allowance for loan losses rollforward
Beginning balance			97	100
Gross charge-offs			0	0
Recoveries			0	0
Net (charge-offs)/ recoveries			0	0
Provision (release)			26	(10)
Other			(1)	0
Ending balance	$ 122	$ 90	$ 122	$ 90
Percent of loans to total loans	28.00%	30.00%	28.00%	30.00%
Allowance for lending commitments rollforward
Beginning balance			$ 4	$ 4
Provision (release)			0	0
Other			1	0
Ending balance	$ 5	$ 4	5	4
Total ending balance	127	94	127	94
SBL and Other
Allowance for loan losses rollforward
Beginning balance			256	212
Gross charge-offs			(17)	(2)
Recoveries			0	3
Net (charge-offs)/ recoveries			(17)	1
Provision (release)			48	35
Other			1	(2)
Ending balance	$ 288	$ 246	$ 288	$ 246
Percent of loans to total loans	41.00%	42.00%	41.00%	42.00%
Allowance for lending commitments rollforward
Beginning balance			$ 17	$ 20
Provision (release)			(1)	(1)
Other			0	0
Ending balance	$ 16	$ 19	16	19
Total ending balance	$ 304	$ 265	$ 304	$ 265

Allowance For Credit Loss And Exposures

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- Definition

Amount of other addition (reduction) in allowance reserve for credit loss.

+ References

No definition available.

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Financing Receivable, Loans Held for Investment by Loan Type to Total Loans Held for Investment

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- Definition

A valuation allowance for credit exposures related to off-balance-sheet loan commitments.

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Other increase (decrease) in the allowance for credit exposures on off-balance-sheet loan commitments.

+ References

No definition available.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
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Amount, excluding accrued interest, of decrease (increase) in allowance for credit loss on financing receivable from writeoff (recovery). Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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- Definition

Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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-Topic 220
-SubTopic 40
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-Publisher FASB
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Amount of expense (reversal of expense) for expected credit loss for off-balance sheet credit exposure. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

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