Finance Receivables and Loans, Net (Consumer Concentration Risk) (Details) - Consumer portfolio segment	Dec. 31, 2020	Dec. 31, 2019
Automotive loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	100.00%	100.00%
Automotive loan | CALIFORNIA AND TEXAS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	24.70%	24.90%
Automotive loan | CALIFORNIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	8.60%	8.50%
Automotive loan | TEXAS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	12.50%	12.40%
Automotive loan | FLORIDA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	8.80%	8.80%
Automotive loan | PENNSYLVANIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	4.50%	4.60%
Automotive loan | ILLINOIS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	4.00%	4.10%
Automotive loan | NORTH CAROLINA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	4.10%	4.00%
Automotive loan | GEORGIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.90%	3.90%
Automotive loan | NEW YORK
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.20%	3.10%
Automotive loan | OHIO
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.50%	3.60%
Automotive loan | NEW JERSEY
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	2.90%	2.80%
Automotive loan | OTHER UNITED STATES
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	44.00%	44.20%
Mortgage Finance operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	100.00%	100.00%
Mortgage Finance operations | CALIFORNIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	34.30%	35.10%
Mortgage Finance operations | TEXAS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	8.00%	6.50%
Mortgage Finance operations | FLORIDA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	5.50%	5.10%
Mortgage Finance operations | PENNSYLVANIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	2.00%	1.90%
Mortgage Finance operations | ILLINOIS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.00%	2.60%
Mortgage Finance operations | NORTH CAROLINA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	2.30%	2.00%
Mortgage Finance operations | GEORGIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.10%	2.80%
Mortgage Finance operations | NEW YORK
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	3.40%	3.00%
Mortgage Finance operations | OHIO
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	0.50%	0.50%
Mortgage Finance operations | NEW JERSEY
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	2.20%	2.30%
Mortgage Finance operations | OTHER UNITED STATES
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	35.70%	38.20%