Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2019

Retirement Plans [Abstract]

Net Periodic Benefit Cost

	Pension Benefits
	For the three months ended				For the nine months ended
	September 30,				September 30,
($ in millions)	2019		2018		2019		2018
Components of total pension benefit cost
Service cost	$	21	$	22	$	63	$	70
Interest cost on projected benefit obligation		33		31		98		91
Expected return on plan assets		(43)		(45)		(129)		(143)
Amortization of unrecognized loss		14		4		42		17
Net periodic pension benefit cost	$	25	$	12	$	74	$	35
Pension settlement costs		-		9		-		34
Total pension benefit cost	$	25	$	21	$	74	$	69
	Postretirement Benefits
	For the three months ended				For the nine months ended
	September 30,				September 30,
($ in millions)	2019		2018		2019		2018
Components of net periodic postretirement benefit cost
Service cost	$	4	$	5	$	14	$	16
Interest cost on projected benefit obligation		10		9		31		28
Amortization of prior service cost (credit)		(3)		(1)		(7)		(6)
Amortization of unrecognized (gain) loss		1		-		(1)		1
Net periodic postretirement benefit cost	$	12	$	13	$	37	$	39