Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2024

Retirement Benefits [Abstract]

Schedule of Components of Net Cost (Benefit) for Pension and Other Postretirement Plans

Components of net cost (benefit) for pension and other postretirement plans
	Three months ended September 30,				Nine months ended September 30,
($ in millions)	2024		2023		2024		2023
Pension benefits
Service cost	$	26	$	34	$	52	$	99
Interest cost	59		58		175		176
Expected return on plan assets	(74)		(78)		(227)		(234)
Costs and expenses	11		14		—		41
Remeasurement of projected benefit obligation	233		(211)		140		(156)
Remeasurement of plan assets	(214)		369		(129)		219
Remeasurement (gains) losses	19		158		11		63
Pension net cost	$	30	$	172	$	11	$	104
Postretirement benefits
Service cost	$	—	$	—	$	—	$	—
Interest cost	2		3		7		8
Amortization of prior service credit	—		(6)		(1)		(18)
Costs and expenses	2		(3)		6		(10)
Remeasurement of benefit obligation	7		(9)		4		(7)
Remeasurement of plan assets	—		—		—		—
Remeasurement (gains) losses	7		(9)		4		(7)
Postretirement net cost (benefit)	$	9	$	(12)	$	10	$	(17)
Pension and postretirement benefits
Costs and expenses	$	13	$	11	$	6	$	31
Remeasurement (gains) losses	26		149		15		56
Total net cost	$	39	$	160	$	21	$	87

Schedule of Pension and Postretirement Benefits Remeasurement Gains and Losses

Pension and postretirement benefits remeasurement gains and losses
	Three months ended September 30,				Nine months ended September 30,
($ in millions)	2024		2023		2024		2023
Remeasurement of benefit obligation (gains) losses:
Discount rate	$	213	$	(231)	$	115	$	(180)
Other assumptions	27		11		29		17
Remeasurement of plan assets (gains) losses	(214)		369		(129)		219
Remeasurement (gains) losses	$	26	$	149	$	15	$	56