Investments Low Income Housing Tax Credits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Investments, All Other Investments [Abstract]
Low Income Housing Tax Credits	$ 10.5us-gaap_InvestmentTaxCredit	$ 10.4us-gaap_InvestmentTaxCredit
Amortization of Low Income Housing Investments	(5.8)	(5.8)
Tax Benefits from Low Income Housing Investments	$ 4.7	$ 4.6

The amount deducted from an entities' taxes, reflecting a percentage of an amount invested in certain assets spread over the useful life of those assets; includes deferred investment tax credits.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Name:	us-gaap_InvestmentTaxCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration