Unsecured Exchangeable Senior Notes Unsecured Exchangeable Senior Notes (Narrative) (details) (3.625% exchangeable senior notes [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
Feb. 18, 2014
3.625% exchangeable senior notes [Member]
Debt Instrument [Line Items]
Coupon/Stated Rate	3.625%
Repayments of unseucred senior notes	$ 747.5

The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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