Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2023

Retirement Benefits [Abstract]

Schedule of company's pension and postretirement benefit plans

Components of net cost (benefit) for pension and other postretirement plans
	Three months ended March 31,
($ in millions)	2023		2022
Pension benefits
Service cost	$	33	$	29
Interest cost	60		46
Expected return on plan assets	(77)		(110)
Amortization of prior service credit	—		(13)
Costs and expenses	16		(48)
Remeasurement of projected benefit obligation	123		(752)
Remeasurement of plan assets	(180)		529
Remeasurement (gains) losses	(57)		(223)
Pension net benefit	$	(41)	$	(271)
Postretirement benefits
Service cost	$	—	$	—
Interest cost	3		2
Amortization of prior service credit	(6)		(6)
Costs and expenses	(3)		(4)
Remeasurement of projected benefit obligation	4		(24)
Remeasurement of plan assets	—		—
Remeasurement (gains) losses	4		(24)
Postretirement net cost (benefit)	$	1	$	(28)
Pension and postretirement benefits
Costs and expenses	$	13	$	(52)
Remeasurement (gains) losses	(53)		(247)
Total net benefit	$	(40)	$	(299)

Pension and postretirement benefits remeasurement gains and losses
	Three months ended March 31,
($ in millions)	2023		2022
Remeasurement of projected benefit obligation (gains) losses:
Discount rate	$	124	$	(585)
Other assumptions	3		(191)
Remeasurement of plan assets (gains) losses	(180)		529
Remeasurement (gains) losses	$	(53)	$	(247)