Fair Value (Fair Value, by Balance Sheet Grouping) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 4,655	$ 4,680
Loans held-for-sale, net	358	400
Finance receivables and loans, net	134,410	135,852
Deposit liabilities	155,084	154,666
Short-term borrowings	0	3,297
Long-term debt	17,011	17,570
Carrying value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,655	4,680
Loans held-for-sale, net	331	375
Finance receivables and loans, net	134,410	135,852
FHLB/FRB stock	641	784
Deposit liabilities	51,095	55,187
Short-term borrowings		3,297
Long-term debt	17,011	17,570
Estimated fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,633	4,729
Loans held-for-sale, net	331	375
Finance receivables and loans, net	136,081	137,244
FHLB/FRB stock	641	784
Deposit liabilities	51,101	55,311
Short-term borrowings		3,335
Long-term debt	17,938	18,538
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
Long-term debt	0	0
Estimated fair value \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	4,633	4,729
Loans held-for-sale, net		0
Finance receivables and loans, net	0	0
FHLB/FRB stock	641	784
Deposit liabilities	0	0
Short-term borrowings		0
Long-term debt	12,717	12,789
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	331	375
Finance receivables and loans, net	136,081	137,244
FHLB/FRB stock	0	0
Deposit liabilities	51,101	55,311
Short-term borrowings		3,335
Long-term debt	$ 5,221	$ 5,749

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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