Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2026

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 March 31,
($ in millions)	2026		2025
Pension benefits
Service cost	$	30	$	25
Interest cost	58		60
Expected return on plan assets	(82)		(78)
Costs and expenses	6		7
Remeasurement of projected benefit obligation	(82)		53
Remeasurement of plan assets	103		23
Remeasurement (gains) losses	21		76
Pension net cost	$	27	$	83
Postretirement benefits
Service cost	$	—	$	—
Interest cost	2		2
Amortization of prior service credit	(1)		—
Costs and expenses	1		2
Remeasurement of benefit obligation	(2)		2
Remeasurement (gains) losses	(2)		2
Postretirement net (benefit) cost	$	(1)	$	4
Pension and postretirement benefits
Costs and expenses	$	7	$	9
Remeasurement (gains) losses	19		78
Total net cost	$	26	$	87

Schedule of Pension and Postretirement Benefits Remeasurement Gains and Losses

Pension and postretirement benefits remeasurement gains and losses
	Three months ended March 31,
($ in millions)	2026		2025
Remeasurement of benefit obligation (gains) losses:
Discount rate	$	(73)	$	59
Other assumptions	(11)		(4)
Remeasurement of plan assets (gains) losses	103		23
Remeasurement (gains) losses	$	19	$	78