Troubled Debt Restructures and Nonperforming Receivables - Additional Information Related to TDR Loans (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Receivables [Abstract]
Average balance of TDR Loans	$ 470	$ 3,909	$ 990	$ 5,695
Interest income recognized on TDR Loans	$ 2	$ 80	$ 35	$ 330

Financing receivable modifications average recorded investment.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration