Finance Receivables and Loans, Net (Schedule of Accounts, Notes, Loans and Financing Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Derivative, Amount of Hedged Item	315	331
Loans and Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	359	110
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	76,843	74,065
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	65,793	64,292
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Derivative, Amount of Hedged Item	43	66
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,050	9,773
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	8,294	6,413
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 30	44
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | One year, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	3.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Three years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	38.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Four years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	39.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Two years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Five years, or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 2,756	3,360
Held For Investment Mortgage Finance Receivables Interest Only Mortgage Loans	$ 714	941
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | One year, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	23.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Four years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	0.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Two years, or less [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	2.00%
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Five years, or greater [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest-only mortgage loan portfolio principal amortization	1.00%
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 42,101	37,535
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	35,041	31,469
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,248	2,640
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 3,812	$ 3,426