Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 1,255	$ 1,568
Loans held-for-sale, net	441	158
Finance receivables and loans, net	114,649	126,968
Deposit liabilities	134,938	120,752
Short-term borrowings	3,032	5,531
Long-term debt	25,704	34,027
Reported value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	1,255	1,568
Loans held-for-sale, net	285	128
Finance receivables and loans, net	114,641	126,957
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	843	1,150
Deposit liabilities	57,616	60,146
Short-term borrowings	3,032	5,531
Long-term debt	25,704	34,027
Estimate of fair value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	1,336	1,600
Loans held-for-sale, net	285	128
Finance receivables and loans, net	121,363	130,837
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	843	1,150
Deposit liabilities	58,505	60,678
Short-term borrowings	3,033	5,532
Long-term debt	28,672	36,927
Estimate of fair value measurement \| Fair value, inputs, 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
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	0	0
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Estimate of fair value measurement \| Fair value, inputs, level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	1,336	1,600
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	843	1,150
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	19,763	22,789
Estimate of fair value measurement \| Fair value, inputs, level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0	0
Loans held-for-sale, net	285	128
Finance receivables and loans, net	121,363	130,837
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	0	0
Deposit liabilities	58,505	60,678
Short-term borrowings	3,033	5,532
Long-term debt	$ 8,909	$ 14,138

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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