Receivables - Retrospective Review of Trouble Debt Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
New TDR Loan Volumes In The Period [Abstract]
Modifications, primarily interest rate modifications	$ 40	$ 80	$ 100	$ 164
Re-age of past due account	66	137	157	325
Total	$ 106	$ 217	257	$ 489
Amount reclassified as re-ages			$ 160