Annual report pursuant to Section 13 and 15(d)

Postretirement Health Care and Life Insurance Benefits (Weighted Average Assumptions Used To Determine Projected Benefit Obligations For Postretirement Obligations) (Details)

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Postretirement Health Care and Life Insurance Benefits (Weighted Average Assumptions Used To Determine Projected Benefit Obligations For Postretirement Obligations) (Details) (Postretirement Obligations)
Jan. 28, 2012
Jan. 29, 2011
Postretirement Obligations
   
Discount rate 4.65% 5.40%