Business Segments - Narrative (Details) $ in Trillions	12 Months Ended
	Dec. 31, 2019 USD ($) segment
Segment Reporting Information [Line Items]
Number of major reportable business segments	4
Commercial Banking
Segment Reporting Information [Line Items]
Number of primary client segments	3
Asset & Wealth Management
Segment Reporting Information [Line Items]
AWM client assets | $	$ 3.2