Shares Held In Trust Treated As Treasury Shares (Details) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	May 31, 2008	Dec. 31, 2011	Jan. 01, 2011
Shares Held In Trust Treated As Treasury Shares [Line Items]
Shares held in trust		0.7
PSU Plan [Member]
Shares Held In Trust Treated As Treasury Shares [Line Items]
Common stock shares issued to trustee	2.3
Common stock shares distributed from trustee share		0.2
Shares held in trust			0.6
Restated EISPP [Member]
Shares Held In Trust Treated As Treasury Shares [Line Items]
Common stock shares distributed from trustee share		0.2