Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 2,461	$ 2,362
Loans held-for-sale, net	275	314
Finance receivables and loans, net	127,928	128,684
Deposit liabilities	116,325	106,178
Short-term borrowings	6,519	9,987
Long-term debt	37,466	44,193
Estimate of fair value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,499	2,307
Loans held-for-sale, net	253	306
Finance receivables and loans, net	131,383	130,878
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,226	1,351
Deposit liabilities	56,575	51,997
Short-term borrowings	6,523	9,992
Long-term debt	40,175	45,646
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	2,499	2,307
Loans held-for-sale, net	0	0
Finance receivables and loans, net	0	0
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,226	1,351
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	23,441	23,846
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	253	306
Finance receivables and loans, net	131,383	130,878
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	0	0
Deposit liabilities	56,575	51,997
Short-term borrowings	6,523	9,992
Long-term debt	16,734	21,800
Reported value measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	2,461	2,362
Loans held-for-sale, net	253	306
Finance receivables and loans, net	127,928	128,684
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	1,226	1,351
Deposit liabilities	56,084	51,985
Short-term borrowings	6,519	9,987
Long-term debt	$ 37,466	$ 44,193

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

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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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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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