Pensions and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2015

Pension Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Net Periodic Benefit Cost

The net periodic pension and other post-retirement benefit costs for the three and six months ended June 30, 2015 and 2014 were as follows:

	Pensions
	Three Months Ended June 30						Six Months Ended June 30
($ in millions)	2015			2014			2015			2014
Service cost	$	15		$	14		$	30		$	27
Interest cost	53			59			103			118
Expected return on plan assets	(69		)	(74		)	(139		)	(148		)
Amortization of actuarial losses	25			20			55			40
Amortization of prior service credit	—			(1		)	(1		)	(1		)
Settlement losses	—			5			—			5
Curtailments and special termination benefits	1			—			1			—
Net periodic pension benefit cost	$	25		$	23		$	49		$	41

Other Postretirement Benefit Plan [Member]

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Net Periodic Benefit Cost

	Other Postretirement Benefits
	Three Months Ended June 30						Six Months Ended June 30
($ in millions)	2015			2014			2015			2014
Service cost	$	5		$	5		$	10		$	9
Interest cost	12			13			24			25
Amortization of actuarial losses (gains)	8			(3		)	16			(5		)
Amortization of prior service (credit) cost	(2		)	3			(5		)	7
Net periodic other postretirement benefit cost	$	23		$	18		$	45		$	36