Acquisitions and Divestitures (Purchase Price Allocation) (Details) - USD ($) $ in Thousands			3 Months Ended
		Nov. 30, 2017	Mar. 31, 2018		Dec. 31, 2017		Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash and due from banks			$ 459,820		$ 639,073
Trading securities			1,759,430		1,416,345
Loans held-for-sale	[1]		770,412		699,377
Securities available-for-sale			4,826,155		5,170,255
Securities held-to-maturity			10,000		10,000
Loans, net of unearned income			27,249,793	[2]	27,658,929	[2]	$ 19,090,074
Allowance for loan losses			(187,194)		(189,555)		(201,968)	$ (202,068)
CBF Goodwill			1,398,501		1,386,853		191,371	191,371
Other intangible assets			174,415		184,389
Premises and equipment			531,981		532,251
OREO	[3]		35,715		43,382
Other assets			1,943,221		1,723,189
Total assets			40,463,195		41,423,388
Liabilities:
Deposits			30,818,951		30,620,362
Securities sold under agreements to repurchase			672,154		656,602
Other short-term borrowings			1,332,141		2,626,213
Term borrowings			1,214,967		1,218,097
Other liabilities			504,817		549,234
Total liabilities			35,890,667		36,842,900
Consideration paid:
Goodwill			1,398,501		1,386,853		$ 191,371	$ 191,371
Capital Bank Financial Corp
Assets:
CBF Goodwill			1,158,549
Assets As Recorded:
Cash and cash equivalents			205,999
Trading securities			0
Loans held-for-sale			125,344
Securities available-for-sale			1,193,393
Securities held-to-maturity			0
Loans			7,276,741
Allowance for loan losses			0
Other intangible assets			141,207
Premises and equipment			232,506
OREO			33,566
Other assets			658,985
Total assets acquired			9,867,741
Liabilities As Recorded:
Deposits			8,140,102
Securities sold under agreements to repurchase			26,664
Other short-term borrowings			390,391
Term borrowings			187,169
Other liabilities			65,631
Total liabilities assumed			8,809,957
Net assets acquired			1,057,784
Consideration paid:
Equity			(1,792,741)
Cash		$ (423,600)	(423,592)
Total consideration paid		(2,200,000)	(2,216,333)
Goodwill			1,158,549
Capital Bank Financial Corp | Fair Value Adjustments
Assets:
Cash and due from banks			0		0
Trading securities			0		(4,758)
Loans held-for-sale			(8,659)		134,003
Securities available-for-sale			0		175,526
Securities held-to-maturity			0		(177,549)
Loans, net of unearned income			1,064		(320,372)
Allowance for loan losses			0		45,711
CBF Goodwill			0		(231,292)
Other intangible assets			(2,593)		119,302
Premises and equipment			(846)		37,054
OREO			(362)		(9,149)
Other assets			433		41,320
Total assets			(10,963)		(190,204)
Liabilities:
Deposits			(642)		(849)
Securities sold under agreements to repurchase			0		0
Other short-term borrowings			0		0
Term borrowings			0		67,683
Other liabilities			1,345		4,291
Total liabilities			703		71,125
Net assets acquired			(11,666)		(261,329)
Consideration paid:
Goodwill			$ 0		$ (231,292)
Capital Bank Financial Corp
Assets:
Cash and due from banks		205,999
Trading securities		4,758
Loans held-for-sale		0
Securities available-for-sale		1,017,867
Securities held-to-maturity		177,549
Loans, net of unearned income		7,596,049
Allowance for loan losses		(45,711)
CBF Goodwill		231,292
Other intangible assets		24,498
Premises and equipment		196,298
OREO		43,077
Other assets		617,232
Total assets		10,068,908
Liabilities:
Deposits		8,141,593
Securities sold under agreements to repurchase		26,664
Other short-term borrowings		390,391
Term borrowings		119,486
Other liabilities		59,995
Total liabilities		8,738,129
Net assets acquired		1,330,779
Consideration paid:
Goodwill		$ 231,292

[1] March 31, 2018 and December 31, 2017 include $9.1 million and $11.7 million, respectively, of held-for-sale consumer mortgage loans secured by residential real estate in process of foreclosure.(b)

[2] March 31, 2018 and December 31, 2017 include $21.5 million and $22.7 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.

[3] March 31, 2018 and December 31, 2017 include $6.4 million and $6.3 million, respectively, of foreclosed residential real estate.