Indebtedness (Details) - Mar. 01, 2015 - Senior Notes [Member] - USD ($) $ in Millions	Total
5.125% Senior Notes [Member]
Unsecured Notes [Abstract]
Debt Instrument, Repurchased Face Amount	$ 300
Interest Rate	5.125%
3.75% Senior Notes [Member]
Unsecured Notes [Abstract]
Debt Instrument, Face Amount	$ 400
Interest Rate	3.75%

Face (par) amount of debt instrument at time of issuance.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant