Business Segments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) segment
Segment Reporting Information [Line Items]
Number of major reportable business segments | segment	4
Asset & Wealth Management
Segment Reporting Information [Line Items]
AWM client assets	$ 2,700,000
Minimum | Commercial Banking
Segment Reporting Information [Line Items]
Annual client revenue	20
Maximum | Commercial Banking
Segment Reporting Information [Line Items]
Annual client revenue	$ 2,000