For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.1)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1, 2, 3

-Article 9

Name:	us-gaap_CashAndDueFromBanks
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Components of Net Interest Income (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Net Interest Income [Line Items]
Cash and Due from Banks	$ 4,074.8us-gaap_CashAndDueFromBanks	$ 3,050.6us-gaap_CashAndDueFromBanks	$ 3,676.3us-gaap_CashAndDueFromBanks	$ 3,162.4us-gaap_CashAndDueFromBanks
Interest-Bearing Deposits with Banks	15,432.3us-gaap_InterestBearingDepositsInBanks	14,928.3us-gaap_InterestBearingDepositsInBanks
Bank Time Deposits
Net Interest Income [Line Items]
Cash and Due from Banks	$ 2,200.0