Regulation and Capital Adequacy - Risk-Based Capital Ratios (Detail) - Group Inc. $ in Millions	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Standardized
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital	$ 104,297	$ 103,065
Tier 1 capital	118,943	115,647
Tier 2 capital	11,722	14,125
Total capital	130,665	129,772
RWAs	$ 727,338	$ 688,541
CET1 capital ratio	0.143	0.150
Tier 1 capital ratio	0.164	0.168
Total capital ratio	0.180	0.188
Advanced
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 capital	$ 104,297	$ 103,065
Tier 1 capital	118,943	115,647
Tier 2 capital	9,527	10,164
Total capital	128,470	125,811
RWAs	$ 691,470	$ 674,812
CET1 capital ratio	0.151	0.153
Tier 1 capital ratio	0.172	0.171
Total capital ratio	0.186	0.186

Amount of total capital as defined by regulatory framework.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

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