Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2025

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)	2025		2024		2025		2024
Pension benefits
Service cost (1)	$	28	$	26	$	79	$	52
Interest cost	58		59		177		175
Expected return on plan assets	(77)		(74)		(233)		(227)
Costs and expenses	9		11		23		—
Remeasurement of projected benefit obligation	20		233		128		140
Remeasurement of plan assets	(127)		(214)		(158)		(129)
Remeasurement (gains) losses	(107)		19		(30)		11
Pension net (benefit) cost	$	(98)	$	30	$	(7)	$	11
Postretirement benefits
Service cost	$	—	$	—	$	—	$	—
Interest cost	2		2		6		7
Amortization of prior service credit	(1)		—		(1)		(1)
Costs and expenses	1		2		5		6
Remeasurement of benefit obligation	(1)		7		—		4
Remeasurement of plan assets	—		—		—		—
Remeasurement (gains) losses	(1)		7		—		4
Postretirement net cost	$	—	$	9	$	5	$	10
Pension and postretirement benefits
Costs and expenses	$	10	$	13	$	28	$	6
Remeasurement (gains) losses	(108)		26		(30)		15
Total net (benefit) cost	$	(98)	$	39	$	(2)	$	21

(1)    For the first nine months of 2024, service cost includes a $38 million refund of premiums previously paid to the Pension Benefit Guaranty Corporation.

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)	2025		2024		2025		2024
Remeasurement of benefit obligation (gains) losses:
Discount rate	$	29	$	213	$	93	$	115
Other assumptions	(10)		27		35		29
Remeasurement of plan assets (gains) losses	(127)		(214)		(158)		(129)
Remeasurement (gains) losses	$	(108)	$	26	$	(30)	$	15