Accumulated Other Comprehensive Loss (Tables)
 3 Months Ended
Mar. 31, 2016
Accumulated Other Comprehensive Income [Abstract]  
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
($ in millions)
Unrealized Foreign
Currency
Translation Adjustments
 
Pension and Other Postretirement Benefit Adjustments, net of tax
 
Unrealized Gain (Loss) on Derivatives, net of tax
 
Accumulated
Other Comprehensive
(Loss) Income
Balance, January 1, 2016
 
 
$
(1,332
)
 
 
 
$
(1,379
)
 
 
 
$
9

 
 
 
$
(2,702
)
Current year deferrals to AOCI
49

(a) 
 
 
—

 
 
 
—

 
 
 
49

 
 
Current year deferrals to AOCI, tax effected
(1
)
(b) 
 
 
6

(c) 
 
 
2

(d) 
 
 
7

 
 
Reclassifications from AOCI to net income
—

 
 
 
13

 
 
 
(10
)
 
 
 
3

 
 
Net change
 
 
$
48

 
 
 
$
19

 
 
 
$
(8
)
 
 
 
$
59

Balance, March 31, 2016
 
 
$
(1,284
)
 
 
 
$
(1,360
)
 
 
 
$
1

 
 
 
$
(2,643
)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Balance, January 1, 2015
 
 
$
(628
)
 
 
 
$
(1,492
)
 
 
 
$
4

 
 
 
$
(2,116
)
Current year deferrals to AOCI
(429
)
(a) 
 
 
—

 
 
 
—

 
 
 
(429
)
 
 
Current year deferrals to AOCI, tax effected
162

(b) 
 
 
45

(c) 
 
 
(33
)
(d) 
 
 
174

 
 
Reclassifications from AOCI to net income
—

 
 
 
23

 
 
 
39

 
 
 
62

 
 
Net change
 
 
$
(267
)
 
 
 
$
68

 
 
 
$
6

 
 
 
$
(193
)
Balance, March 31, 2015
 
 
$
(895
)
 
 
 
$
(1,424
)
 
 
 
$
10

 
 
 
$
(2,309
)

(a) - Unrealized foreign currency translation adjustments related to the translation of foreign denominated balance sheet account balances are not presented net of tax given that no deferred U.S. income taxes have been provided on the undistributed earnings of non-U.S. subsidiaries because they are deemed to be reinvested for an indefinite period of time.
(b) - The tax (benefit) cost related to unrealized foreign currency translation adjustments on tax inter-branch transactions and net investment hedges for the three months ended March 31, 2016 and 2015 was $(17) million and $51 million, respectively. The balance also includes a remeasurement of the tax cost on certain foreign proceeds which have not been permanently reinvested.
(c) - The tax cost related to the adjustment for pension and other postretirement benefits for the three months ended March 31, 2016 and 2015 was $20 million and $24 million, respectively. Reclassifications from AOCI are included in the computation of net periodic pension and other post-retirement benefit costs (See Note 10, "Pensions and Other Postretirement Benefits").
(d) - The tax (benefit) cost related to the changes in the unrealized gain on derivatives for the three months ended March 31, 2016 and 2015 was $(4) million and $2 million, respectively. Reclassifications from AOCI are included in the gain recognized on cash flow hedges (See Note 13, "Financial Instruments, Hedging Activities and Fair Value Measurements").