Fair Value - Schedule of Fair Value, by Balance Sheet Grouping (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 4,286	$ 4,371
Loans held-for-sale, net	406	549
Finance receivables and loans, net	140,097	133,964
Deposit liabilities	154,046	151,649
Short-term borrowings	5,916	4,695
Long-term debt	17,053	17,070
Carrying value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,286	4,371
Loans held-for-sale, net	406	549
Finance receivables and loans, net	140,097	133,964
FHLB/FRB stock	847	811
Deposit liabilities	42,274	42,310
Short-term borrowings	5,916	4,695
Long-term debt	17,053	17,070
Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,299	4,451
Loans held-for-sale, net	407	560
Finance receivables and loans, net	143,558	137,579
FHLB/FRB stock	847	811
Deposit liabilities	42,338	42,523
Short-term borrowings	5,841	4,706
Long-term debt	18,159	18,349
Estimated fair value \| Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0	0
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
FHLB/FRB stock	0	0
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Estimated fair value \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,299	4,451
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
FHLB/FRB stock	847	811
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	12,392	12,642
Estimated fair value \| Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0	0
Loans held-for-sale, net	407	560
Finance receivables and loans, net	143,558	137,579
FHLB/FRB stock	0	0
Deposit liabilities	42,338	42,523
Short-term borrowings	5,841	4,706
Long-term debt	$ 5,767	$ 5,707

Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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