Subsequent Event (Details) (USD $) In Millions, except Share data, unless otherwise specified		1 Months Ended	6 Months Ended	0 Months Ended	6 Months Ended
	Aug. 02, 2011	Jul. 31, 2011 New Corporate Office Building [Member] years	Jul. 01, 2011 New Corporate Office Building [Member]	Aug. 03, 2011 Share Repurchase [Member]	Jul. 01, 2011 Share Repurchase [Member]
Lease, Term		20
Subsequent Event, Date			Jul. 20, 2011		Aug. 02, 2011
Stock Repurchase Program, Authorized Amount				$ 300
Approximate Outstanding Shares At Aug. 2, 2011	144
Lease Expiration Date			2033
Lease Commitment, Approximate		$ 116