Consolidated Statements of Changes in Equity (Parenthetical) (USD $)	3 Months Ended	12 Months Ended
Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Changes in Equity
Dividends paid (in dollars per share)	$ 0.085	$ 0.085	$ 0.085	$ 0.085	$ 0.080	$ 0.080	$ 0.080	$ 0.080	$ 0.075	$ 0.075	$ 0.075	$ 0.075	$ 0.43	$ 0.32	$ 0.30

Aggregate dividends paid during the period for each share of common stock outstanding.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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