Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2014

Retirement Plans [Abstract]

Net Periodic Benefit Cost

	Pension Benefits
	For the three months ended				For the six months ended
	June 30,				June 30,
	2014		2013		2014		2013
($ in thousands)
Components of net periodic pension benefit cost
Service cost	$	9,940	$	12,834	$	19,880	$	25,668
Interest cost on projected benefit obligation		19,824		18,880		39,648		37,760
Expected return on plan assets		(23,512)		(24,590)		(47,024)		(49,180)
Amortization of prior service cost /(credit)		11		2		22		4
Amortization of unrecognized loss		4,819		10,072		9,638		20,144
Net periodic pension benefit cost	$	11,082	$	17,198	$	22,164	$	34,396

	Postretirement Benefits
	Other Than Pensions (OPEB)
	For the three months ended				For the six months ended
	June 30,				June 30,
	2014		2013		2014		2013
($ in thousands)
Components of net periodic postretirement benefit cost
Service cost	$	2,553	$	3,179	$	5,106	$	6,358
Interest cost on projected benefit obligation		4,788		4,440		9,576		8,880
Expected return on plan assets		(7)		(43)		(14)		(86)
Amortization of prior service cost/(credit)		(890)		(1,525)		(1,780)		(3,050)
Amortization of unrecognized loss		722		2,228		1,444		4,456
Net periodic postretirement benefit cost	$	7,166	$	8,279	$	14,332	$	16,558