Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Share activity

Activity in the number of shares of common stock and treasury stock was as follows (in millions):

	Common Stock	Treasury Stock
Balance as of December 31, 2014	673	(159	)
Transactions in connection with stock-based compensation plans	—	1
Stock purchases under purchase program	—	(42	)
Balance as of December 31, 2015	673	(200	)
Transactions in connection with stock-based compensation plans	—	1
Stock purchases under purchase program	—	(23	)
Balance as of December 31, 2016	673	(222	)
Transactions in connection with stock-based compensation plans	—	1
Stock purchases under purchase program	—	(19	)
Balance as of December 31, 2017	673	(240	)

Income tax effects related to components of other comprehensive income (loss)

The tax effects allocated to each component of other comprehensive income (loss) were as follows (in millions):

	Before-Tax Amount			Tax Expense (Benefit)			Net Amount
Year Ended December 31, 2017:
Foreign currency translation adjustment	$	514		$	—		$	514
Pension and other postretirement benefits:
Loss arising during the year related to:
Net actuarial loss	(79		)	(29		)	(50		)
Prior service cost	(4		)	(1		)	(3		)
Miscellaneous loss	—			3			(3		)
Amounts reclassified into income related to:
Net actuarial loss	50			18			32
Prior service credit	(36		)	(13		)	(23		)
Curtailment and settlement loss	4			1			3
Net loss on pension and other postretirement benefits	(65		)	(21		)	(44		)
Other comprehensive income	$	449		$	(21	)	$	470

	Before-Tax Amount			Tax Expense (Benefit)			Net Amount
Year Ended December 31, 2016:
Foreign currency translation adjustment	$	(415	)	$	—		$	(415	)
Pension and other postretirement benefits:
Gain (loss) arising during the year related to:
Net actuarial loss	(110		)	(34		)	(76		)
Miscellaneous gain	—			(8		)	8
Amounts reclassified into income related to:
Net actuarial loss	48			18			30
Prior service credit	(36		)	(13		)	(23		)
Net loss on pension and other postretirement benefits	(98		)	(37		)	(61		)
Other comprehensive loss	$	(513	)	$	(37	)	$	(476	)

Year Ended December 31, 2015:
Foreign currency translation adjustment	$	(606	)	$	—		$	(606	)
Pension and other postretirement benefits:
Gain (loss) arising during the year related to:
Net actuarial gain	50			15			35
Prior service cost	(22		)	(8		)	(14		)
Amounts reclassified into income related to:
Net actuarial loss	62			22			40
Prior service credit	(40		)	(14		)	(26		)
Curtailment and settlement loss	7			2			5
Net gain on pension and other postretirement benefits	57			17			40
Other comprehensive loss	$	(549	)	$	17		$	(566	)

Changes in components of accumulated other comprehensive income (loss)

Changes in accumulated other comprehensive income (loss) by component, net of tax, were as follows (in millions):

	Foreign Currency Translation Adjustment			Defined Benefit Plan Items			Total
Balance as of December 31, 2014	$	1		$	(368	)	$	(367	)
Other comprehensive income (loss) before reclassifications	(606		)	21			(585		)
Amounts reclassified from accumulated other comprehensive  income (loss)	—			19			19
Net other comprehensive income (loss)	(606		)	40			(566		)
Balance as of December 31, 2015	(605		)	(328		)	(933		)
Other comprehensive loss before reclassifications	(416		)	(68		)	(484		)
Amounts reclassified from accumulated other comprehensive loss	—			7			7
Net other comprehensive loss	(416		)	(61		)	(477		)
Balance as of December 31, 2016	(1,021		)	(389		)	(1,410		)
Other comprehensive income (loss) before reclassifications	514			(56		)	458
Amounts reclassified from accumulated other comprehensive  loss	—			12			12
Net other comprehensive income (loss)	514			(44		)	470
Balance as of December 31, 2017	$	(507	)	$	(433	)	$	(940	)

Gains (losses) reclassified out of accumulated other comprehensive income (loss)

Gains (losses) reclassified out of accumulated other comprehensive loss and into net income were as follows (in millions):

Details about Accumulated Other Comprehensive Loss Components										Affected Line Item in the Statement of Income
	Year Ended December 31,
	2017			2016			2015
Amortization of items related to defined benefit pension plans:
Net actuarial loss	$	(50	)	$	(48	)	$	(62	)	(a)
Prior service credit	36			36			40			(a)
Curtailment and settlement	(4		)	—			(7		)	(a)
	(18		)	(12		)	(29		)	Total before tax
	6			5			10			Tax benefit
Total reclassifications for the year	$	(12	)	$	(7	)	$	(19	)	Net of tax

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(a) These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost, as further discussed in Note 12. Net periodic benefit cost is reflected in operating expenses (excluding depreciation and amortization expense) and general and administrative expenses (excluding depreciation and amortization expense).