Benefit Plans (Tables)

9 Months Ended

Sep. 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 September 30,				Nine months ended September 30,
($ in millions)	2023		2022		2023		2022
Pension benefits
Service cost	$	34	$	22	$	99	$	79
Interest cost	58		59		176		157
Expected return on plan assets	(78)		(85)		(234)		(295)
Amortization of prior service credit	—		(2)		—		(27)
Costs and expenses	14		(6)		41		(86)
Remeasurement of projected benefit obligation	(211)		(254)		(156)		(1,427)
Remeasurement of plan assets	369		335		219		1,563
Remeasurement (gains) losses	158		81		63		136
Pension net cost	$	172	$	75	$	104	$	50
Postretirement benefits
Service cost	$	—	$	—	$	—	$	1
Interest cost	3		3		8		7
Amortization of prior service credit	(6)		(7)		(18)		(19)
Costs and expenses	(3)		(4)		(10)		(11)
Remeasurement of projected benefit obligation	(9)		(2)		(7)		(45)
Remeasurement of plan assets	—		—		—		—
Remeasurement (gains) losses	(9)		(2)		(7)		(45)
Postretirement net benefit	$	(12)	$	(6)	$	(17)	$	(56)
Pension and postretirement benefits
Costs and expenses	$	11	$	(10)	$	31	$	(97)
Remeasurement (gains) losses	149		79		56		91
Total net cost (benefit)	$	160	$	69	$	87	$	(6)

Pension and postretirement benefits remeasurement gains and losses
	Three months ended September 30,				Nine months ended September 30,
($ in millions)	2023		2022		2023		2022
Remeasurement of projected benefit obligation (gains) losses:
Discount rate	$	(231)	$	(284)	$	(180)	$	(1,289)
Other assumptions	11		28		17		(183)
Remeasurement of plan assets (gains) losses	369		335		219		1,563
Remeasurement (gains) losses	$	149	$	79	$	56	$	91