Business Segments (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) branch segment
Business segments
Reportable business segments | segment	5
Consumer and Business Banking Division | California
Business segments
Number of full-service branches | branch	349
Consumer and Business Banking Division | Washington and Oregon
Business segments
Number of full-service branches | branch	26
Commercial Banking | Minimum
Business segments
Corporate customers revenues	$ 20
Commercial Banking | Maximum
Business segments
Corporate customers revenues	2,000
U.S. Middle Market Banking [Member] | Maximum
Business segments
Corporate customers revenues	1,000
Mid-Corporate Banking [Member] | Maximum
Business segments
Corporate customers revenues	2,000
Corporate Banking | Minimum
Business segments
Corporate customers revenues	$ 2,000