Accumulated Other Comprehensive Loss
 3 Months Ended
Mar. 31, 2018
Equity [Abstract]  
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss
The following table shows the changes in accumulated other comprehensive loss by component. Amounts in parentheses indicate debits.
(In millions)
Pension Benefits
 
Other Benefits
 
Gain on Cash Flow Hedge
 
Workers Compensation
 
Total
Balance as of December 31, 2016
$
(233
)
 
$
(7
)
 
$
4

 
$
2

 
$
(234
)
Other comprehensive loss before reclassifications
(1
)
 
—

 
—

 
—

 
(1
)
Amounts reclassified from accumulated other comprehensive loss:
 
 
 
 
 
 
 
 
 
Amortization – prior service credit(a)
(10
)
 
(1
)
 
—

 
—

 
(11
)
   – actuarial loss(a)
9

 
—

 
—

 
—

 
9

   – settlement loss(a)
—

 
—

 
—

 
—

 
—

Tax effect
—

 
—

 
—

 
—

 
—

Other comprehensive loss
(2
)
 
(1
)
 
—

 
—

 
(3
)
Balance as of March 31, 2017
$
(235
)
 
$
(8
)
 
$
4

 
$
2

 
$
(237
)
(In millions)
Pension Benefits
 
Other Benefits
 
Gain on Cash Flow Hedge
 
Workers Compensation
 
Total
Balance as of December 31, 2017
$
(190
)
 
$
(48
)
 
$
4

 
$
3

 
$
(231
)
Other comprehensive loss before reclassifications
—

 
—

 
(2
)
 
—

 
(2
)
Amounts reclassified from accumulated other comprehensive loss:
 
 
 
 
 
 
 
 
 
Amortization – prior service credit(a)
(8
)
 
(1
)
 
—

 
—

 
(9
)
   – actuarial loss(a)
9

 
—

 
—

 
—

 
9

   – settlement loss(a)
1

 
—

 
—

 
—

 
1

Tax effect
(1
)
 
—

 
—

 
—

 
(1
)
Other comprehensive income (loss)
1

 
(1
)
 
(2
)
 
—

 
(2
)
Balance as of March 31, 2018
$
(189
)
 
$
(49
)
 
$
2

 
$
3

 
$
(233
)
(a) 
These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost. See Note 20.