Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	$ 118	$ 0
Loans held-for-sale, net	39	105
Total finance receivables and loans, net	109,799	110,546
Nonmarketable equity investments	733	418
Deposit liabilities	70,265	66,478
Short-term borrowings	5,365	8,101
Long-term debt	62,044	66,234
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	118
Loans held-for-sale, net	39	105
Total finance receivables and loans, net	109,799	110,546
Nonmarketable equity investments	733	418
Deposit liabilities	70,265	66,478
Short-term borrowings	5,365	8,101
Long-term debt	62,044	66,234
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0
Loans held-for-sale, net	0	0
Total finance receivables and loans, net	0	0
Nonmarketable equity investments	0	0
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	118
Loans held-for-sale, net	0	0
Total finance receivables and loans, net	0	0
Nonmarketable equity investments	706	391
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	22,252	23,018
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	0
Loans held-for-sale, net	39	105
Total finance receivables and loans, net	110,596	110,737
Nonmarketable equity investments	42	42
Deposit liabilities	70,849	66,889
Short-term borrowings	5,365	8,102
Long-term debt	41,463	45,157
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held-to-maturity securities	118
Loans held-for-sale, net	39	105
Total finance receivables and loans, net	110,596	110,737
Nonmarketable equity investments	748	433
Deposit liabilities	70,849	66,889
Short-term borrowings	5,365	8,102
Long-term debt	$ 63,715	$ 68,175