Troubled Debt Restructures and Nonperforming Receivables - Nonperforming Portfolio (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables		$ 256	$ 5,674
Delinquency threshold for loss reserves		90 days
Nonaccrual loans carried at lower of amortized cost of fair value less cost to sell but less than 90 days delinquent		$ 35	252
Accruing Receivables [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables		232	5,293
Nonaccrual Receivables [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Receivables	[1]	$ 24	$ 381

[1] Nonaccrual receivables are all receivables which are 90 or more days contractually delinquent as well as second lien receivables (regardless of delinquency status) where the first lien receivable that we own or service is 90 or more days contractually delinquent. Nonaccrual receivables do not include receivables which have made qualifying payments and have been re-aged such that the contractual delinquency status has been reset to current. If a re-aged receivable subsequently experiences payment default and becomes 90 or more days contractually delinquent, it will be reported as nonaccrual. Nonaccrual receivables do not include receivables totaling $35 million and $252 million at September 30, 2017 and December 31, 2016, respectively, which are less than 90 days contractually delinquent and not accruing interest.