Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2023

Retirement Benefits [Abstract]

Schedule of Change in Projected Benefit Obligation, Plan Assets and Funded Status

Change in projected benefit obligation, plan assets and funded status
	As of December 31,
	Pension benefits				Postretirement benefits
($ in millions)	2023		2022		2023		2022
Change in projected benefit obligation
Benefit obligation, beginning of year	$	4,511	$	6,500	$	203	$	284
Service cost	132		101		1		1
Interest cost	239		219		10		10
Participant contributions	—		—		16		16
Remeasurement of projected benefit obligation (gains) losses	125		(1,382)		(4)		(62)
Benefits paid	(379)		(894)		(42)		(42)
Translation adjustment and other	(44)		(33)		1		(4)
Benefit obligation, end of year	$	4,584	$	4,511	$	185	$	203
Change in plan assets
Fair value of plan assets, beginning of year	$	4,430	$	6,525
Actual return on plan assets	418		(1,189)
Employer contribution	14		24
Benefits paid	(379)		(894)
Translation adjustment and other	(43)		(36)
Fair value of plan assets, end of year	$	4,440	$	4,430
Funded status (1)	$	(144)	$	(81)	$	(185)	$	(203)
Amounts recognized in AOCI
Unamortized pension and other postretirement prior service credit	$	—	$	—	$	(18)	$	(39)

(1)The funded status is recorded within other assets or other liabilities and accrued expenses on the Consolidated Statements of Financial Position.

Schedule of Changes in Items Not Yet Recognized as a Component of Net Cost for Pension and Other Postretirement Plans

Changes in items not yet recognized as a component of net cost for pension and other postretirement plans
($ in millions)	Pension benefits		Postretirement benefits
Items not yet recognized as a component of net cost – December 31, 2022	$	—	$	(39)
Prior service credit amortized to net cost	—		21
Translation adjustment and other	—		—
Items not yet recognized as a component of net cost – December 31, 2023	$	—	$	(18)

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

Components of net cost (benefit) for pension and other postretirement plans
	For the years ended December 31,
	Pension benefits						Postretirement benefits						Total pension and postretirement benefits
($ in millions)	2023		2022		2021		2023		2022		2021		2023		2022		2021
Service cost	$	132	$	101	$	103	$	1	$	1	$	1	$	133	$	102	$	104
Interest cost	239		219		191		10		10		8		249		229		199
Expected return on plan assets	(306)		(371)		(445)		—		—		—		(306)		(371)		(445)
Amortization of prior service credit	—		(27)		(50)		(21)		(25)		(25)		(21)		(52)		(75)
Costs and expenses	65		(78)		(201)		(10)		(14)		(16)		55		(92)		(217)
Remeasurement of projected benefit obligation	125		(1,382)		(309)		(4)		(62)		(16)		121		(1,444)		(325)
Remeasurement of plan assets	(112)		1,560		(319)		—		—		—		(112)		1,560		(319)
Remeasurement (gains) losses	13		178		(628)		(4)		(62)		(16)		9		116		(644)
Total net (benefit) cost	$	78	$	100	$	(829)	$	(14)	$	(76)	$	(32)	$	64	$	24	$	(861)

Schedule of Weighted Average Assumptions Used to Determine Net Pension Cost and Net Postretirement Benefit Cost and Benefit Obligations

Weighted average assumptions used to determine net pension cost and net postretirement benefit cost
	For the years ended December 31,
	Pension benefits						Postretirement benefits
	2023		2022		2021		2023		2022		2021
Discount rate	5.65	%	4.27	%	2.84	%	5.66	%	4.24	%	2.75	%
Expected long-term rate of return on plan assets	7.35		7.06		7.06		n/a		n/a		n/a
Cash balance interest credit rate	4.05		2.74		2.04		n/a		n/a		n/a

Weighted average assumptions used to determine benefit obligations
	As of December 31,
	Pension benefits				Postretirement benefits
	2023		2022		2023		2022
Discount rate	5.35	%	5.64	%	5.28	%	5.58	%
Cash balance interest credit rate	4.03		3.97		n/a		n/a

Schedule of Weighted Average Target Asset Allocation and Actual Percentage of Plan Assets by Asset Category

Weighted average target asset allocation and actual percentage of plan assets by asset category
	As of December 31, 2023
	Target asset allocation (1)	Actual percentage of plan assets
Pension plan’s asset category	2023	2023		2022
Equity securities	17 - 36%	26	%	27	%
Fixed income securities	38 - 54	48		49
Limited partnership interests	1 - 29	23		21
Short-term investments and other	NA	3		3
Total without securities lending (2)		100	%	100	%

(1)The target asset allocation considers risk-based exposure while the actual percentage of plan assets utilizes a financial reporting view excluding exposure provided through derivatives.

(2)Securities lending collateral reinvestment of $180 million and $297 million is excluded from the table above in 2023 and 2022, respectively.

Schedule of Fair Values of Pension Plan Assets

Fair values of pension plan assets as of December 31, 2023
($ in millions)	Quoted prices in active markets for identical assets (Level 1)			Significant other observable inputs (Level 2)			Significant unobservable inputs (Level 3)			Balance as of December 31, 2023
Equity securities	$	132		$	28		$	—		$	160
Fixed income securities:
Government bonds (1)	323			1,007			—			1,330
Corporate bonds (2)	—			794			—			794
Short-term investments	154			144			—			298
Free-standing derivatives:
Assets	—			—			—			—
Liabilities	(1)			(8)			—			(9)
Other assets	1			—			—			1
Total plan assets at fair value	$	609		$	1,965		$	—		2,574
% of total plan assets at fair value	23.7		%	76.3		%	—		%	100.0		%
Investments measured using the net asset value practical expedient										2,019
Securities lending obligation (3)										(179)
Derivatives counterparty and cash collateral netting										8
Other net plan assets (4)										18
Total reported plan assets										$	4,440

Fair values of pension plan assets as of December 31, 2022
($ in millions)	Quoted prices in active markets for identical assets (Level 1)			Significant other observable inputs (Level 2)			Significant unobservable inputs (Level 3)			Balance as of December 31, 2022
Equity securities	$	120		$	25		$	—		$	145
Fixed income securities:
Government bonds (1)	496			896			—			1,392
Corporate bonds (2)	—			757			—			757
Short-term investments	163			279			—			442
Free-standing derivatives:
Assets	—			1			—			1
Liabilities	(1)			(5)			—			(6)
Other assets	1			—			—			1
Total plan assets at fair value	$	779		$	1,953		$	—		$	2,732
% of total plan assets at fair value	28.5		%	71.5		%	—		%	100.0		%
Investments measured using the net asset value practical expedient										$	1,975
Securities lending obligation (3)										(296)
Derivatives counterparty and cash collateral netting										2
Other net plan assets (4)										17
Total reported plan assets										$	4,430

(1)Includes U.S. government and agencies and foreign government bonds.

(2)Includes ABS securities.

(3)The securities lending obligation represents the plan’s obligation to return securities lending collateral received under a securities lending program. The terms of the program allow both the plan and the counterparty the right and ability to redeem/return the securities loaned on short notice. Due to its relatively short-term nature, the outstanding balance of the obligation approximates fair value.

(4)Other net plan assets represent cash and cash equivalents, interest and dividends receivable and net receivables related to settlements of investment transactions, such as purchases and sales.

Schedule of Rollforward of Level 3 Plan Assets

Rollforward of Level 3 plan assets during December 31, 2023

Actual return on plan assets:

($ in millions)

Balance as of December 31, 2022

Relating to assets sold during the period

Relating to assets still held at the reporting date

Purchases, sales and settlements, net

Net transfers in (out) of Level 3

Balance as of December 31, 2023

Equity securities

$

—

$

—

$

—

$

—

$

—

$

—

Total Level 3 plan assets

$

—

$

—

$

—

$

—

$

—

$

—

Rollforward of Level 3 plan assets during December 31, 2022
			Actual return on plan assets:
($ in millions)	Balance as of December 31, 2021		Relating to assets sold during the period		Relating to assets still held at the reporting date		Purchases, sales and settlements, net		Net transfers in (out) of Level 3		Balance as of December 31, 2022
Equity securities	$	2	$	—	$	—	$	—	$	(2)	$	—
Total Level 3 plan assets	$	2	$	—	$	—	$	—	$	(2)	$	—

Rollforward of Level 3 plan assets during December 31, 2021
			Actual return on plan assets:
($ in millions)	Balance as of December 31, 2020		Relating to assets sold during the period		Relating to assets still held at the reporting date		Purchases, sales and settlements, net		Net transfers in (out) of Level 3		Balance as of December 31, 2021
Equity securities	$	—	$	—	$	—	$	2	$	—	$	2
Fixed income securities:
Corporate	$	2	$	—	$	—	$	(2)	$	—	$	—
Total Level 3 plan assets	$	2	$	—	$	—	$	—	$	—	$	2

Schedule of Estimated Future Benefit Payments Expected to be Paid

Estimated future benefit payments expected to be paid in the next 10 years
	As of December 31, 2023
($ in millions)	Pension benefits		Postretirement benefits
2024	$	495	$	23
2025	487		23
2026	488		21
2027	477		20
2028	472		18
2029-2033	1,740		60
Total benefit payments	$	4,159	$	165