Discontinued and Held-for-sale Operations (Select Balance Sheet Information for Held-for-sale Operations) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Due from Banks	$ 1,043	$ 1,073
Interest-bearing Deposits in Banks and Other Financial Institutions	6,394	6,440
Total cash and cash equivalents	7,437	7,513	13,079	13,035
Available-for-sale Securities	15,752	14,178
Finance receivables and loans, net	99,123	99,055	118,986
Loans and Leases Receivable, Allowance	(1,197)	(1,170)
Total finance receivables and loans, net	97,926	97,885
Investment in operating leases, net	14,828	13,550
Premiums receivable and other insurance assets	1,608	1,609
Other Assets	7,950	11,908
Total assets	166,199	182,347	186,350
Interest-bearing deposit liabilities	49,482	45,938
Short-term borrowings	7,618	7,461
Long-term debt	67,621	74,561
Interest payable	972	932
Unearned insurance premiums and service revenue	2,286	2,296
Accrued expenses and other liabilities	3,669	6,585
Total liabilities	145,725	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	4	8
Interest-bearing Deposits in Banks and Other Financial Institutions	66	119
Total cash and cash equivalents	70	127
Available-for-sale Securities	418	576
Finance receivables and loans, net	0	0
Loans and Leases Receivable, Allowance	0	0
Total finance receivables and loans, net	0	0
Investment in operating leases, net	0	0
Premiums receivable and other insurance assets	257	277
Other Assets	70	94
Impairment on assets of held-for-sale operations		(53)
Total assets	815	1,021
Interest-bearing deposit liabilities	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Interest payable	0	0
Unearned insurance premiums and service revenue	417	506
Accrued expenses and other liabilities	221	297
Total liabilities	638	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	150	100
Interest-bearing Deposits in Banks and Other Financial Institutions	514	1,918
Total cash and cash equivalents	664	2,018
Available-for-sale Securities	3	424
Finance receivables and loans, net	15,175	25,835
Loans and Leases Receivable, Allowance	(177)	(208)
Total finance receivables and loans, net	14,998	25,627
Investment in operating leases, net	128	144
Premiums receivable and other insurance assets	0	0
Other Assets	2,455	2,942
Impairment on assets of held-for-sale operations		0
Total assets	18,248	31,155
Interest-bearing deposit liabilities	17	3,907
Short-term borrowings	3,059	2,800
Long-term debt	8,092	13,514
Interest payable	155	177
Unearned insurance premiums and service revenue	0	0
Accrued expenses and other liabilities	1,272	1,498
Total liabilities	12,595	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	154	108
Interest-bearing Deposits in Banks and Other Financial Institutions	580	2,037
Total cash and cash equivalents	734	2,145
Available-for-sale Securities	421	1,000
Finance receivables and loans, net	15,175	25,835
Loans and Leases Receivable, Allowance	(177)	(208)
Total finance receivables and loans, net	14,998	25,627
Investment in operating leases, net	128	144
Premiums receivable and other insurance assets	257	277
Other Assets	2,525	3,036
Impairment on assets of held-for-sale operations		(53)
Total assets	19,063	32,176
Interest-bearing deposit liabilities	17	3,907
Short-term borrowings	3,059	2,800
Long-term debt	8,092	13,514
Interest payable	155	177
Unearned insurance premiums and service revenue	417	506
Accrued expenses and other liabilities	1,493	1,795
Total liabilities	$ 13,233	$ 22,699