Finance Receivables - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables	$ 54,888	$ 54,343	$ 54,274
Retail loans and leases threshold delinquent (percent) (more than)	10.00%
Retail loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables	$ 50,201	49,649
Collateral Pledged \| Retail loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables	$ 15,800	$ 16,100

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-3

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

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