Finance Receivables And Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 99,123	$ 99,055	$ 118,986
Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	55,014	53,715
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	9,672	9,821
First Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	7,095	7,173
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	2,577	2,648
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	34,437	35,519
Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	29,255	30,270
Commercial And Industrial Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	0	0
Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	2,562	2,697
Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	2,620	2,552
Commercial Real Estate Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	0	0
Foreign [Member] | Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	1	2
Foreign [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	15	18
loans held-for-investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 842	$ 895