Benefit Plans (Tables)

6 Months Ended

Jun. 30, 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 June 30,				Six months ended June 30,
($ in millions)	2023		2022		2023		2022
Pension benefits
Service cost	$	32	$	28	$	65	$	57
Interest cost	58		52		118		98
Expected return on plan assets	(79)		(100)		(156)		(210)
Amortization of prior service credit	—		(12)		—		(25)
Costs and expenses	11		(32)		27		(80)
Remeasurement of projected benefit obligation	(68)		(421)		55		(1,173)
Remeasurement of plan assets	30		699		(150)		1,228
Remeasurement (gains) losses	(38)		278		(95)		55
Pension net (benefit) cost	$	(27)	$	246	$	(68)	$	(25)
Postretirement benefits
Service cost	$	—	$	1	$	—	$	1
Interest cost	2		2		5		4
Amortization of prior service credit	(6)		(6)		(12)		(12)
Costs and expenses	(4)		(3)		(7)		(7)
Remeasurement of projected benefit obligation	(2)		(19)		2		(43)
Remeasurement of plan assets	—		—		—		—
Remeasurement (gains) losses	(2)		(19)		2		(43)
Postretirement net benefit	$	(6)	$	(22)	$	(5)	$	(50)
Pension and postretirement benefits
Costs and expenses	$	7	$	(35)	$	20	$	(87)
Remeasurement (gains) losses	(40)		259		(93)		12
Total net (benefit) cost	$	(33)	$	224	$	(73)	$	(75)

Pension and postretirement benefits remeasurement gains and losses
	Three months ended June 30,				Six months ended June 30,
($ in millions)	2023		2022		2023		2022
Remeasurement of projected benefit obligation (gains) losses:
Discount rate	$	(73)	$	(420)	$	51	$	(1,005)
Other assumptions	3		(20)		6		(211)
Remeasurement of plan assets (gains) losses	30		699		(150)		1,228
Remeasurement (gains) losses	$	(40)	$	259	$	(93)	$	12