Finance Receivables And Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 105,173		$ 105,173		$ 99,948
Interest and Fee Income, Loans and Leases	1,118	$ 1,124	2,192	$ 2,231
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	1,100		1,100		1,200
Loans Receivable, Fair Value Disclosure	1		1		1
Consumer Loans Auto Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	60,786		60,786		56,570
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	9,212		9,212		7,474
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	35,175		35,175		35,904
Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	29,732		29,732		30,871
Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	2,149		2,149		1,882
Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	3,294		3,294		3,151
loans held-for-investment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	57		57		266
Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest and Fee Income, Loans and Leases	2	$ 18	35	$ 29
Fair Value Option Election, Fair Value [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables and loans, net	$ 105,173		105,173		99,948
Fair Value Option Election, Fair Value [Member] | Designated as Hedging Instrument [Member] | Gain (Loss) Recognized in Earnings on Hedged Item [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest and Fee Income, Loans and Leases			$ 69		$ 35
One year or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	12.00%		12.00%
Two years or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	33.00%		33.00%
Three years or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	21.00%		21.00%
Four years or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	2.00%		2.00%
Five years or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	4.00%		4.00%