Acquisitions and Divestitures (Narrative) (Details) $ in Thousands		3 Months Ended	4 Months Ended
	Apr. 03, 2017 USD ($)	Jun. 30, 2016 USD ($)	May 04, 2017 USD ($) branch	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 16, 2016 USD ($)
Business Acquisition [Line Items]
Total assets				$ 29,369,956		$ 28,555,231
Capital Bank Financial Corp
Business Acquisition [Line Items]
Total assets					$ 10,000,000
Number of bank branches operated | branch			193
Expected cash payment to acquire business, gross			$ 411,000
Percentage of outstanding common shares (percent)			29.00%
Total transaction value			$ 2,200,000
GE Capital Member
Business Acquisition [Line Items]
Loans acquired							$ 537,400
Coastal Securities
Business Acquisition [Line Items]
Payments to acquire business	$ 131,473
Goodwill	$ 45,000
FHN and Coastal
Business Acquisition [Line Items]
Acquisition-related expenses		$ 6,400