Fair Value - Schedule of Fair Value, by Balance Sheet Grouping (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 4,668	$ 4,346
Loans held-for-sale, net	209	160
Finance receivables and loans, net	130,087	132,316
Deposit liabilities	151,428	151,574
Short-term borrowings	3,339	1,625
Long-term debt	16,465	17,495
Carrying value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,668	4,346
Loans held-for-sale, net	203	144
Finance receivables and loans, net	130,087	132,316
FHLB/FRB stock	693	698
Deposit liabilities	42,459	47,242
Short-term borrowings	3,339	1,625
Long-term debt	16,465	17,495
Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,670	4,293
Loans held-for-sale, net	203	144
Finance receivables and loans, net	132,614	134,603
FHLB/FRB stock	693	698
Deposit liabilities	42,591	47,403
Short-term borrowings	3,345	1,625
Long-term debt	17,531	18,517
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	4,670	4,293
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
FHLB/FRB stock	693	698
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	12,880	13,535
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	203	144
Finance receivables and loans, net	132,614	134,603
FHLB/FRB stock	0	0
Deposit liabilities	42,591	47,403
Short-term borrowings	3,345	1,625
Long-term debt	$ 4,651	$ 4,982

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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