Discontinued and Held-for-sale Operations (Select Balance Sheet Information for Held-for-sale Operations) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Due from Banks	$ 1,063		$ 1,073
Interest-bearing Deposits in Banks and Other Financial Institutions	5,486		6,440
Total cash and cash equivalents	6,549		7,513	17,157		13,035
Available-for-sale Securities	17,967		14,178
Finance receivables and loans, net	95,281		99,055	121,259
Loans and Leases Receivable, Allowance	(1,198)	(1,183)	(1,170)	(1,423)	(1,427)	(1,503)
Total finance receivables and loans, net	94,083		97,885
Investment in operating leases, net	17,254		13,550
Premiums receivable and other insurance assets	1,649		1,609
Other Assets	7,059		11,908
Total assets	150,556		182,347	182,482
Interest-bearing deposit liabilities	51,965		45,938
Short-term borrowings	6,015		7,461
Long-term debt	60,701		74,561
Interest payable	978		932
Unearned insurance premiums and service revenue	2,332		2,296
Accrued expenses and other liabilities	4,836		6,585
Total liabilities	131,495		162,449
Insurance Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Due from Banks			8
Interest-bearing Deposits in Banks and Other Financial Institutions			119
Total cash and cash equivalents			127
Available-for-sale Securities			576
Finance receivables and loans, net			0
Loans and Leases Receivable, Allowance			0
Total finance receivables and loans, net			0
Investment in operating leases, net			0
Premiums receivable and other insurance assets			277
Other Assets			94
Impairment on assets of held-for-sale operations			(53)
Total assets			1,021
Interest-bearing deposit liabilities			0
Short-term borrowings			0
Long-term debt			0
Interest payable			0
Unearned insurance premiums and service revenue			506
Accrued expenses and other liabilities			297
Total liabilities			803
Automotive finance operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Due from Banks	35		100
Interest-bearing Deposits in Banks and Other Financial Institutions	158		1,918
Total cash and cash equivalents	193		2,018
Available-for-sale Securities			424
Finance receivables and loans, net	4,308		25,835
Loans and Leases Receivable, Allowance	(94)		(208)
Total finance receivables and loans, net	4,214		25,627
Investment in operating leases, net			144
Premiums receivable and other insurance assets			0
Other Assets	1,506		2,942
Impairment on assets of held-for-sale operations			0
Total assets	5,913		31,155
Interest-bearing deposit liabilities			3,907
Short-term borrowings	521		2,800
Long-term debt	3,455		13,514
Interest payable	117		177
Unearned insurance premiums and service revenue			0
Accrued expenses and other liabilities	509		1,498
Total liabilities	4,602		21,896
Discontinued Operation Or Assets Disposal [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Due from Banks			108
Interest-bearing Deposits in Banks and Other Financial Institutions			2,037
Total cash and cash equivalents			2,145
Available-for-sale Securities			1,000
Finance receivables and loans, net			25,835
Loans and Leases Receivable, Allowance			(208)
Total finance receivables and loans, net			25,627
Investment in operating leases, net			144
Premiums receivable and other insurance assets			277
Other Assets			3,036
Impairment on assets of held-for-sale operations			(53)
Total assets			32,176
Interest-bearing deposit liabilities			3,907
Short-term borrowings			2,800
Long-term debt			13,514
Interest payable			177
Unearned insurance premiums and service revenue			506
Accrued expenses and other liabilities			1,795
Total liabilities			$ 22,699