Stock-Based Compensation Plans (Details 3) (Restricted Stock Units)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)	1,151,318	924,576	652,120
Weighted average vesting period (years)	3 years	3 years	3 years

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration