Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2021

Retirement Plans [Abstract]

Net Periodic Benefit Cost

	Pension Benefits
	For the three months ended
	March 31,
($ in millions)	2021		2020
Components of total pension benefit cost
Service cost	$	24	$	25
Interest cost on projected benefit obligation		23		30
Expected return on plan assets		(45)		(50)
Amortization of unrecognized loss		18		17
Net periodic pension benefit cost		20		22
Pension settlement costs		-		103
Total pension benefit cost	$	20	$	125
	Postretirement Benefits
	For the three months ended
	March 31,
($ in millions)	2021		2020
Components of net periodic postretirement benefit cost
Service cost	$	5	$	5
Interest cost on projected benefit obligation		7		8
Amortization of prior service cost (credit)		(7)		(8)
Amortization of unrecognized (gain) loss		3		2
Net periodic postretirement benefit cost	$	8	$	7