Finance Receivables and Loans, Net (Schedule of Pass And Criticized Credit Quality Indicators of Finance Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 118,944	$ 111,600
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	42,101	37,535
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	39,410	35,000
Commercial Portfolio Segment [Member] | Commercial Loan [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,691	2,535
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	35,041	31,469
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	33,160	29,613
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,881	1,856
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,248	2,640
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,597	2,122
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	651	518
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,812	3,426
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,653	3,265
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member] | Criticized [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 159	$ 161