Acquisitions and Divestitures (Purchase Price Allocation) (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
		Nov. 30, 2017	Jun. 30, 2018		Jun. 30, 2018		Mar. 31, 2018	Dec. 31, 2017		Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Assets:
Cash and cash equivalents			$ 602,952		$ 602,952			$ 639,073
Trading securities			1,649,470		1,649,470			1,416,345
Loans held-for-sale	[1]		692,659		692,659			699,377
Securities available-for-sale								5,170,255
Securities held-to-maturity			10,000		10,000			10,000
Loans			27,701,740	[2]	27,701,740	[2]		27,658,929	[2]	$ 19,989,319
Allowance for loan losses			(185,462)		(185,462)		$ (187,194)	(189,555)		(197,257)	$ (201,968)	$ (202,068)
CBF Goodwill			1,409,276		1,409,276			1,386,853		236,335		191,371
Other intangible assets			167,955		167,955			184,389
Premises and equipment			525,175		525,175			532,251
OREO	[3]		29,712		29,712			43,382
Other assets			1,934,001		1,934,001			1,723,189
Total assets			41,076,795		41,076,795			41,423,388
Liabilities:
Deposits			30,977,867		30,977,867			30,620,362
Securities sold under agreements to repurchase			713,152		713,152			656,602
Other short-term borrowings			1,836,852		1,836,852			2,626,213
Term borrowings			1,227,281		1,227,281			1,218,097
Other liabilities			526,430		526,430			549,234
Total liabilities			36,527,046		36,527,046			36,842,900
Consideration paid:
Goodwill			1,409,276		1,409,276			1,386,853		$ 236,335		$ 191,371
Capital Bank Financial Corp
Assets:
CBF Goodwill			1,169,324		1,169,324
Assets As Recorded:
Cash and cash equivalents			205,999		205,999
Trading securities			0		0
Loans held-for-sale			124,918		124,918
Securities available-for-sale		$ 1,200,000	1,193,393		1,193,393
Securities held-to-maturity			0		0
Loans		7,300,000	7,276,544		7,276,544
Allowance for loan losses			0		0
Other intangible assets			141,207		141,207
Premises and equipment			231,447		231,447
OREO			33,613		33,613
Other assets			651,024		651,024
Total assets acquired		9,900,000	9,858,145		9,858,145
Liabilities As Recorded:
Deposits		8,100,000	8,140,102		8,140,102
Securities sold under agreements to repurchase			26,664		26,664
Other short-term borrowings			390,391		390,391
Term borrowings			187,169		187,169
Other liabilities			66,810		66,810
Total liabilities assumed			8,811,136		8,811,136
Net assets acquired			1,047,009		1,047,009
Consideration paid:
Equity					(1,746,724)
Cash		(423,600)	(46,000)		(469,609)
Total consideration paid		(2,200,000)			(2,216,333)
Goodwill			1,169,324		1,169,324
Capital Bank Financial Corp | Purchase Accounting/Fair Value Adjustments
Assets:
Cash and cash equivalents			0		0			0
Trading securities			0		0			(4,758)
Loans held-for-sale			(9,085)		(9,085)			134,003
Securities available-for-sale			0		0			175,526
Securities held-to-maturity			0		0			(177,549)
Loans			867		867			(320,372)
Allowance for loan losses			0		0			45,711
CBF Goodwill			0		0			(231,292)
Other intangible assets			(2,593)		(2,593)			119,302
Premises and equipment			(1,905)		(1,905)			37,054
OREO			(315)		(315)			(9,149)
Other assets			(7,528)		(7,528)			41,320
Total assets			(20,559)		(20,559)			(190,204)
Liabilities:
Deposits			(642)		(642)			(849)
Securities sold under agreements to repurchase			0		0			0
Other short-term borrowings			0		0			0
Term borrowings			0		0			67,683
Other liabilities			2,524		2,524			4,291
Total liabilities			1,882		1,882			71,125
Net assets acquired			(22,441)		(22,441)			(261,329)
Consideration paid:
Goodwill			$ 0		$ 0			$ (231,292)
Capital Bank Financial Corp
Assets:
Cash and cash equivalents		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		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] June 30, 2018 and December 31, 2017 include $8.9 million and $11.7 million, respectively, of held-for-sale consumer mortgage loans secured by residential real estate in process of foreclosure.

[2] June 30, 2018 and December 31, 2017 include $21.4 million and $22.7 million, respectively, of held-to-maturity consumer mortgage loans secured by residential real estate in process of foreclosure.

[3] June 30, 2018 and December 31, 2017 include $6.1 million and $6.3 million, respectively, of foreclosed residential real estate.