Segments (Intersegment Administrative Fee Revenues) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Administrative fees	$ 32.5	$ 32.8	$ 98.3	$ 97.0
Intersegment Eliminations [Member]
Administrative fees	$ 5.1	$ 4.9	$ 15.0	$ 14.5

Amount of fees and commissions from financial services and banking activities and correspondent clearing. Includes fees from depositor accounts, credit cards, merchant discounts, and fiduciary and trust activities, guarantee fees, investment advisory, management, and administrative fees, transfer agent fees, and insurance commissions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.13)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Name:	us-gaap_FeesAndCommissions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration