Securitizations and Variable Interest Entities (Schedule of Cash Flow Received from and Paid to Nonconsolidated Securitization Entities) (Details) - Off-balance sheet variable interest entities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consumer Automotive Industry Sector
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows received on retained interests in securitization entities	$ (23)	$ (20)	$ (21)
Cash flows between transferor and transferee, servicing fees	10	18	31
Cash flows between transferor and transferee, disbursement for repurchases during the period	2	4	491
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers		24	1,187
Cash Flow Between Transferee and Transferor Representations And Warranties Obligations		0
Other cash flows			4
Consumer Mortgage Industry Sector
Cash Flow Received and Paid to Nonconsolidated Securitization Entities [Line Items]
Cash flows received on retained interests in securitization entities	0	0	0
Cash flows between transferor and transferee, servicing fees	0	0	0
Cash flows between transferor and transferee, disbursement for repurchases during the period	$ 0	0	0
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers		0	0
Cash Flow Between Transferee and Transferor Representations And Warranties Obligations		$ 2
Other cash flows			$ 0