Retirement Benefit Plans (Net Periodic Expense) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Jan. 28, 2012
Jan. 29, 2011
Jan. 30, 2010
Service cost $ 90 $ 89 $ 83
Interest cost 260 262 270
Projected return on assets (385) (352) (304)
Amortization of prior service (credit) 156 256 288
Net periodic plan expense/(income) 121 255 337
Benefits Plan Primary Plan [Member]
      
Service cost 88 88 80
Interest cost 247 248 253
Projected return on assets (385) (352) (304)
Amortization of prior service (credit) 137 237 269
Net periodic plan expense/(income) 87 221 298
Benefits Supplemental Plan [Member]
      
Service cost 2 1 3
Interest cost 13 14 17
Amortization of prior service (credit) 19 19 19
Net periodic plan expense/(income) 34 34 39
Other Postretirement Benefit Plans, Defined Benefit [Member]
      
Interest cost 1 1 1
Amortization of prior service (credit) (26) (26) (26)
Net periodic plan expense/(income) $ (25) $ (25) $ (25)
Description of Defined Contribution Pension and Other Postretirement Plans

Postretirement Benefits — Medical and Dental

We provide medical and dental benefits to retirees through a contributory medical and dental plan based on age and years of service. We provide a defined dollar commitment toward retiree medical premiums.

 

Effective June 7, 2005, we amended the medical plan to reduce our subsidy to post-age 65 retirees and spouses by 45% beginning January 1, 2006, and then fully eliminated the subsidy after December 31, 2006. As disclosed previously, the postretirement benefit plan was amended in 2001 to reduce and cap the per capita dollar amount of the benefit costs that would be paid by the plan. Thus, changes in the assumed or actual health care cost trend rates do not materially affect the accumulated postretirement benefit obligation or our annual expense.