Fair Value - Schedule of Fair Value, by Balance Sheet Grouping (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 4,337	$ 4,371
Loans held-for-sale, net	337	549
Finance receivables and loans, net	136,350	133,964
Deposit liabilities	153,152	151,649
Short-term borrowings	4,126	4,695
Long-term debt	17,349	17,070
Carrying value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,337	4,371
Loans held-for-sale, net	337	549
Finance receivables and loans, net	136,350	133,964
FHLB/FRB stock	789	811
Deposit liabilities	40,215	42,310
Short-term borrowings	4,126	4,695
Long-term debt	17,349	17,070
Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,387	4,451
Loans held-for-sale, net	338	560
Finance receivables and loans, net	139,266	137,579
FHLB/FRB stock	789	811
Deposit liabilities	40,362	42,523
Short-term borrowings	4,123	4,706
Long-term debt	18,360	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	4,387	4,451
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
FHLB/FRB stock	789	811
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	12,891	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	338	560
Finance receivables and loans, net	139,266	137,579
FHLB/FRB stock	0	0
Deposit liabilities	40,362	42,523
Short-term borrowings	4,123	4,706
Long-term debt	$ 5,469	$ 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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