Accumulated Other Comprehensive Loss (Notes)
 9 Months Ended
Sep. 30, 2016
Accumulated Other Comprehensive Income [Abstract]  
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss
($ 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
(157
)
(a) 
 
 
—

 
 
 
—

 
 
 
(157
)
 
 
Current year deferrals to AOCI, tax effected
(73
)
(b) 
 
 
(267
)
(c) 
 
 
(6
)
(d) 
 
 
(346
)
 
 
Reclassifications from AOCI to net income
—

 
 
 
658

(c) 
 
 
6

(d) 
 
 
664

 
 
Net change
 
 
$
(230
)
 
 
 
$
391

 
 
 
$
—

 
 
 
$
161

Balance, September 30, 2016
 
 
$
(1,562
)
 
 
 
$
(988
)
 
 
 
$
9

 
 
 
$
(2,541
)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Balance, January 1, 2015
 
 
$
(628
)
 
 
 
$
(1,492
)
 
 
 
$
4

 
 
 
$
(2,116
)
Current year deferrals to AOCI
(679
)
(a) 
 
 
—

 
 
 
—

 
 
 
(679
)
 
 
Current year deferrals to AOCI, tax effected
88

(b) 
 
 
40

(c) 
 
 
(36
)
(d) 
 
 
92

 
 
Reclassifications from AOCI to net income
—

 
 
 
69

(c) 
 
 
42

(d) 
 
 
111

 
 
Net change
 
 
$
(591
)
 
 
 
$
109

 
 
 
$
6

 
 
 
$
(476
)
Balance, September 30, 2015
 
 
$
(1,219
)
 
 
 
$
(1,383
)
 
 
 
$
10

 
 
 
$
(2,592
)

(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 nine months ended September 30, 2016 and 2015 was $(53) million and $23 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 (benefit) cost related to the adjustment for pension and other postretirement benefits for the nine months ended September 30, 2016 and 2015 was $(252) million and $50 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 nine months ended September 30, 2016 and 2015 was $(1) 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").