Short and Long-Term Funding (Components of Short-term and Long-term Funding) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Short-term Funding [Abstract]
Federal funds purchased		$ 323,365	$ 208,150
Securities sold under agreements to repurchase		326,823	300,197
Federal funds purchased and securities sold under agreements to repurchase		650,188	508,347
FHLB advances		309,000	482,000
Commercial paper		121,679	101,688
Other short-term funding		430,679	583,688
Total short-term funding		1,080,867	1,092,035
Long-term Funding
FHLB advances		2,265,180	2,265,188
Senior notes, at par		250,000	250,000
Subordinated notes, at par		250,000	250,000
Other long-term funding and capitalized costs		(3,225)	(3,393)
Total long-term funding	[1]	2,761,955	2,761,795
Total short and long-term funding		$ 3,842,822	$ 3,853,830

[1] (1)Effective January 1, 2017, residential loans originated for sale are accounted for under the fair value option. Prior periods have not been restated. For more information on this accounting policy change, please refer to Note 3 to the Notes to the Consolidated Financial Statements.