Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Consumer Concentration Risk by State and Foreign Geographic)(Details) - Consumer Portfolio Segment [Member]	Dec. 31, 2017	Dec. 31, 2016
Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	100.00%	100.00%
CALIFORNIA AND TEXAS
Concentration Risk [Line Items]
Consumer Concentration Risk	24.70%	24.20%
CALIFORNIA | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	8.20%	7.80%
CALIFORNIA | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	34.60%	34.20%
TEXAS | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	13.20%	13.60%
TEXAS | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	6.50%	6.60%
FLORIDA | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	8.50%	8.20%
FLORIDA | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	4.80%	4.40%
PENNSYLVANIA | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	4.60%	4.70%
PENNSYLVANIA | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	1.50%	1.50%
ILLINOIS | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	4.20%	4.30%
ILLINOIS | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	3.20%	3.40%
GEORGIA | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	4.20%	4.30%
GEORGIA | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	2.50%	2.20%
NORTH CAROLINA | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	3.70%	3.60%
NORTH CAROLINA | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	1.80%	1.60%
OHIO | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	3.40%	3.50%
OHIO | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	0.50%	0.50%
NEW YORK | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	3.00%	3.20%
NEW YORK | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	2.20%	1.90%
MISSOURI | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	2.90%	2.80%
MISSOURI | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	0.90%	1.20%
United States, Other | Automobile Loan [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	44.10%	44.00%
United States, Other | Residential Mortgage [Member]
Concentration Risk [Line Items]
Consumer Concentration Risk	41.50%	42.50%