Debt Of The Company (Details)	9 Months Ended		9 Months Ended
Sep. 30, 2012 3.625% Notes Due 2022 [Member]	Sep. 30, 2011 3.625% Notes Due 2022 [Member]	Dec. 31, 2011 Exchangeable Senior Debentures [Member]	Sep. 30, 2012 Exchangeable Senior Debentures [Member] 5.50% Exchangeable Senior Debentures Due 2029 [Member]	Sep. 30, 2012 Senior Notes [Member] 4.50% Notes Due 2015 [Member]	Sep. 30, 2012 Senior Notes [Member] 5.875% Notes Due 2020 [Member]	Sep. 30, 2012 Senior Notes [Member] 5.25% Notes Due 2021 [Member]	Sep. 30, 2012 Senior Notes [Member] 3.625% Notes Due 2022 [Member]
Debt Instrument [Line Items]
Interest rate	3.625%	3.625%	4.125%	5.50%	4.50%	5.875%	5.25%	3.625%
Maturity date	2022	2022		2029	2015	2020	2021	2022

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration