Fair Value (Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	$ 1,438	$ 2,003
Total finance receivables and loans, net	104,199	98,971
Nonmarketable equity securities	359	271
Deposit liabilities	61,947	58,222
Short-term borrowings	10,013	7,062
Long-term debt	65,852	66,558
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	0	0
Total finance receivables and loans, net	0	0
Nonmarketable equity securities	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]
Loans held-for-sale, net	0	485
Total finance receivables and loans, net	0	0
Nonmarketable equity securities	333	246
Deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	21,778	25,224
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	1,446	1,554
Total finance receivables and loans, net	105,110	99,430
Nonmarketable equity securities	41	33
Deposit liabilities	62,449	58,777
Short-term borrowings	10,013	7,063
Long-term debt	46,247	44,084
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	1,438	2,003
Total finance receivables and loans, net	104,199	98,971
Nonmarketable equity securities	359	271
Deposit liabilities	61,947	58,222
Short-term borrowings	10,013	7,062
Long-term debt	65,852	66,558
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-sale, net	1,446	2,039
Total finance receivables and loans, net	105,110	99,430
Nonmarketable equity securities	374	279
Deposit liabilities	62,449	58,777
Short-term borrowings	10,013	7,063
Long-term debt	$ 68,025	$ 69,308