Change in Accounting for Retirement-Related Benefits (Tables)
 6 Months Ended
Jul. 30, 2016
Change in Accounting for Retirement-Related Benefits [Abstract]  
Schedule of Prior Period Adjustments Made to Consolidated Statements of Operations [Table Text Block]
Consolidated Statements of Operations
 
Three Months Ended
 
Six Months Ended
 
August 1, 2015
 
August 1, 2015
($ in millions, except per share data)
Previously Reported
 
As Adjusted
 
Effect of Change
 
Previously Reported
 
As Adjusted
 
Effect of Change
Pension
$
13

 
$
(16
)
 
$
(29
)
 
$
23

 
$
(35
)
 
$
(58
)
Income/(loss) before income taxes
(141
)
 
(112
)
 
29

 
(314
)
 
(256
)
 
58

Income tax expense/(benefit)
(3
)
 
5

 
8

 
(9
)
 
11

 
20

Net income/(loss)
$
(138
)
 
(117
)
 
$
21

 
$
(305
)
 
(267
)
 
$
38

Basic earnings/(loss) per common share
$
(0.45
)
 
$
(0.38
)
 
$
0.07

 
$
(1.00
)
 
$
(0.87
)
 
$
0.13

Diluted earnings/(loss) per common share
$
(0.45
)
 
$
(0.38
)
 
$
0.07

 
$
(1.00
)
 
$
(0.87
)
 
$
0.13
Schedule of Prior Period Adjustments Made to Consolidated Statements of Comprehensive Income/(Loss) [Table Text Block]
Consolidated Statements of Comprehensive Income/(Loss)
 
Three Months Ended
 
Six Months Ended
 
August 1, 2015
 
August 1, 2015
($ in millions)
Previously Reported
 
As Adjusted
 
Effect of Change
 
Previously Reported
 
As Adjusted
 
Effect of Change
Net income/(loss)
$
(138
)
 
$
(117
)
 
$
21

 
$
(305
)
 
$
(267
)
 
$
38

Reclassifications for amortization of net actuarial (gain)/loss
18

 
—

 
(18
)
 
35

 
—

 
(35
)
Deferred tax valuation allowance
—

 
(3
)
 
(3
)
 
—

 
(3
)
 
(3
)
Total other comprehensive income/(loss), net of tax
12

 
(9
)
 
(21
)
 
29

 
(9
)
 
(38
)
Total comprehensive income/(loss), net of tax
$
(126
)
 
$
(126
)
 
$
—

 
$
(276
)
 
$
(276
)
 
$
—
Schedule of Prior Period Adjustments Made to Consolidated Balance Sheet [Table Text Block]
Consolidated Balance Sheets
 
August 1, 2015
($ in millions)
Previously Reported
 
As Adjusted
 
Effect of Change
Reinvested earnings/(accumulated deficit)
$
(2,084
)
 
$
(2,761
)
 
$
(677
)
Accumulated other comprehensive income/(loss)
(1,036
)
 
(359
)
 
677
Schedule of Prior Period Adjustments Made to Consolidated Statements of Cash Flows [Table Text Block]
Consolidated Statements of Cash Flows
 
Three Months Ended
 
Six Months Ended
 
August 1, 2015
 
August 1, 2015
($ in millions)
Previously Reported
 
As Adjusted
 
Effect of Change
 
Previously Reported
 
As Adjusted
 
Effect of Change
Cash flows from operating activities:
 
 
 
 
 
 
 
 
 
 
 
Net income/(loss)
$
(138
)
 
$
(117
)
 
$
21

 
$
(305
)
 
$
(267
)
 
$
38

Benefit plans
6

 
(23
)
 
(29
)
 
10

 
(48
)
 
(58
)
Deferred taxes
$
(6
)
 
$
2

 
$
8

 
$
(17
)
 
$
3

 
$
20