Pension and Other Postretirement Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2018

Defined Benefit Plan Disclosure [Line Items]

Components of net cost of defined benefit plans

The Company has defined benefit pension plans covering eligible employees in the United States and in certain of its international subsidiaries. The net periodic benefit cost (credit) of such plans consisted of the following components:



	Three Months Ended June 30,												Six Months Ended June 30,
	2018						2017						2018						2017
($ in millions)	U.S.			International			U.S.			International			U.S.			International			U.S.			International
Service cost	$	85		$	58		$	77		$	63		$	168		$	125		$	154		$	124
Interest cost	107			45			113			42			215			91			226			83
Expected return on plan assets	(211		)	(108		)	(218		)	(97		)	(425		)	(221		)	(436		)	(191		)
Amortization of unrecognized prior service credit	(13		)	(3		)	(13		)	(3		)	(25		)	(7		)	(27		)	(5		)
Net loss amortization	56			21			44			24			112			43			89			47
Termination benefits	7			—			3			1			17			—			8			2
Curtailments	5			(1		)	1			(1		)	3			(1		)	4			(1		)
Settlements	—			4			—			—			1			4			—			—
	$	36		$	16		$	7		$	29		$	66		$	34		$	18		$	59

Other Postretirement Benefit Plans

Defined Benefit Plan Disclosure [Line Items]

Components of net cost of defined benefit plans

The Company provides medical benefits, principally to its eligible U.S. retirees and similar benefits to their dependents, through its other postretirement benefit plans. The net cost (credit) of such plans consisted of the following components:



	Three Months Ended June 30,						Six Months Ended June 30,
($ in millions)	2018			2017			2018			2017
Service cost	$	14		$	14		$	28		$	28
Interest cost	18			20			35			40
Expected return on plan assets	(21		)	(20		)	(41		)	(39		)
Amortization of unrecognized prior service credit	(21		)	(24		)	(42		)	(49		)
Termination benefits	1			—			2			1
Curtailments	(2		)	(2		)	(6		)	(5		)
	$	(11	)	$	(12	)	$	(24	)	$	(24	)