Finance Receivables and Loans, Net (Schedule of Purchases of Financing Receivables and Loans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 899	$ 1,085	$ 2,233	$ 2,548
Consumer portfolio segment | Automotive loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	218	233	317	401
Consumer portfolio segment | Real estate-backed loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	678	852	1,913	2,147
Commercial portfolio segment | Commercial loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables and loans, significant purchases	$ 3	$ 0	$ 3	$ 0