Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2015

Retirement Plans [Abstract]

Net Periodic Benefit Cost

	Pension Benefits
	For the three months ended				For the six months ended
	June 30,				June 30,
	2015		2014		2015		2014
($ in millions)
Components of net periodic pension benefit cost
Service cost	$	14	$	10	$	27	$	20
Interest cost on projected benefit obligation		22		20		44		40
Expected return on plan assets		(32)		(23)		(64)		(47)
Amortization of unrecognized loss		6		4		13		9
Net periodic pension benefit cost	$	10	$	11	$	20	$	22

	Postretirement Benefits
	Other Than Pensions (OPEB)
	For the three months ended				For the six months ended
	June 30,				June 30,
	2015		2014		2015		2014
($ in millions)
Components of net periodic postretirement benefit cost
Service cost	$	4	$	2	$	9	$	5
Interest cost on projected benefit obligation		8		5		15		10
Expected return on plan assets		-		1		-		-
Amortization of prior service cost/(credit)		(1)		(1)		(2)		(2)
Amortization of unrecognized loss		2		-		5		1
Net periodic postretirement benefit cost	$	13	$	7	$	27	$	14