Other Assets (Schedule of Other Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Other Assets [Abstract]
Property and equipment at cost	$ 1,332	$ 1,250
Accumulated depreciation, property and equipment	(686)	(686)
Property and equipment, net	646	564
Nonmarketable equity securities	1,232	1,410
Investments in qualified affordable housing projects	830	649
Restricted cash collections for securitization trusts	738	965
Accrued interest, late fees, and rent receivables	589	599
Goodwill	393	240
Equity method investments	358	262
Other accounts receivable	117	203
Restricted cash and cash equivalents	87	124
Net intangible assets	69	59
Fair value of derivative contracts in receivable position	64	41
Deferred tax assets, net	58	317
Other assets, other	892	720
Total other assets	6,073	6,153
Federal Home Loan Bank stock	701	903
Federal Reserve Bank stock	449	448
Equity securities without a readily determinable fair value	82	59
Equity securities without readily determinable fair value, upward price adjustment, annual amount	9
Equity securities without readily determinable fair value, impairment loss, annual amount	3
Equity securities without readily determinable fair value, upward price adjustment, cumulative amount	10
Impairment related to equity securities without a readily determinable fair value	6
Intangible Assets, Gross (Excluding Goodwill)	111	88
Goodwill [Line Items]
Goodwill	393	240
Accumulated depreciation of intangible assets	42	29
Corporate and Other
Other Assets [Abstract]
Goodwill	346	193
Goodwill [Line Items]
Goodwill	346	193
Goodwill, acquired during period	153
Insurance operations | Operating Segments
Other Assets [Abstract]
Goodwill	27	27
Goodwill [Line Items]
Goodwill	27	27
Automotive Finance operations | Operating Segments
Other Assets [Abstract]
Goodwill	20	20
Goodwill [Line Items]
Goodwill	$ 20	$ 20