Business Segments Additional Information (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) segment	Jun. 30, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment		4
Maximum annual revenue of small business clients to be served by RBWM		$ 3
Operating Segments [Member] | RBWM [Member]
Segment Reporting Information [Line Items]
Increase to loss before tax	$ 8		$ 16