Pension and Other Postretirement Benefits - Summary of Information in Curtailment or Settlement of Benefits Requiring Remeasurement, Update to Discount Rates Used to Determine Benefit Obligations of Affected Plans (Detail) $ in Millions	3 Months Ended						12 Months Ended
	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($) Employees	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($) Employees	Sep. 30, 2021 USD ($)	Dec. 31, 2023 USD ($) Employees	Dec. 31, 2022 USD ($) Employees	Dec. 31, 2021 USD ($) Employees	Apr. 30, 2023	Mar. 31, 2023	Jul. 31, 2022	Nov. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to other noncurrent assets							$ 210	$ 87	$ 160
Action# 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees							370
Weighted average discount rate							5.58%				5.20%
Plan remeasurement date							Mar. 31, 2023
Increase (decrease) to accrued other pension benefits liability		$ 15					$ 15
Decrease to accrued other postretirement benefits		(9)					$ (9)
Action# 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees							530
Weighted average discount rate							5.20%			4.80%
Plan remeasurement date							Apr. 30, 2023
Increase (decrease) to accrued other pension benefits liability		22					$ 22
Increase (decrease) to other noncurrent assets		(5)					(5)
Settlement loss (gain)		$ (21)					$ 21
Action# 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees							50
Weighted average discount rate	5.03%						5.08%
Plan remeasurement date							Sep. 30, 2023
Increase (decrease) to other noncurrent assets	$ (2)						$ (2)
2023 Plan Actions [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees							950
Increase (decrease) to accrued other pension benefits liability							$ 37
Increase (decrease) to other noncurrent assets							(7)
Decrease to accrued other postretirement benefits							(9)
Settlement loss (gain)							$ 21
Action# 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			4,400					4,400
Weighted average discount rate			2.90%					2.90%				4.63%
Plan remeasurement date								Jul. 31, 2022
Increase (decrease) to accrued other pension benefits liability				$ 5				$ 5
Increase (decrease) to other noncurrent assets				27				27
Settlement loss (gain)				(617)				$ 617
Action# 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			45					45
Weighted average discount rate			2.90%					2.90%				4.63%
Plan remeasurement date								Jul. 31, 2022
Settlement loss (gain)				$ (11)				$ 11
Action# 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			5					5
Weighted average discount rate			4.57%	5.71%				4.57%
Plan remeasurement date								Sep. 30, 2022
Increase (decrease) to accrued other pension benefits liability				$ 23				$ 23
Increase (decrease) to other noncurrent assets				(12)				(12)
Settlement loss (gain)				$ (1)				$ 1
Action# 4 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			25					25
Weighted average discount rate			2.46%	4.99%				2.46%
Plan remeasurement date								Sep. 30, 2022
Increase (decrease) to other noncurrent assets				$ 21				$ 21
Settlement loss (gain)				$ 3				$ (3)
Action# 5 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			20					20
Plan remeasurement date								Dec. 31, 2022
Increase (decrease) to accrued other pension benefits liability			$ 3					$ 3
Settlement loss (gain)			$ (6)					$ 6
2022 Plan Actions [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees			4,495					4,495
Increase (decrease) to accrued other pension benefits liability								$ 31
Increase (decrease) to other noncurrent assets								36
Settlement loss (gain)								$ 632
Action# 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					840				840
Weighted average discount rate															3.06%	2.45%
Plan remeasurement date									Mar. 31, 2021
Decrease to accrued other postretirement benefits									$ (106)
Curtailment loss(gain)									17
Settlement loss (gain)									$ 26
Action# 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					120				120
Weighted average discount rate														2.71%		2.38%
Plan remeasurement date									Jun. 30, 2021
Increase (decrease) to accrued other pension benefits liability									$ (90)
Settlement loss (gain)									$ 39
Action# 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					20				20
Weighted average discount rate						2.74%										2.71%
Plan remeasurement date									Sep. 30, 2021
Increase (decrease) to accrued other pension benefits liability						$ 7			$ 7
Settlement loss (gain)						$ (7)			$ 7
Action# 4 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					20				20
Weighted average discount rate						1.53%										1.34%
Plan remeasurement date									Sep. 30, 2021
Increase (decrease) to accrued other pension benefits liability						$ (38)			$ (38)
Settlement loss (gain)						$ (1)			$ 1
Action# 5 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					800				800
Settlement loss (gain)					$ (63)				$ 63
Action# 6 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					14,000				14,000
Weighted average discount rate													2.79%			2.59%
Plan remeasurement date									Nov. 30, 2021
Increase (decrease) to accrued other pension benefits liability					$ (84)				$ (84)
Settlement loss (gain)					$ (848)				$ 848
Action# 7 [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of affected plan participants | Employees					60				60
Weighted average discount rate													2.79%			2.59%
Plan remeasurement date									Nov. 30, 2021
Increase (decrease) to accrued other pension benefits liability					$ (1)				$ (1)
Settlement loss (gain)					$ (10)				10
2021 Plan Actions [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to accrued other pension benefits liability									(206)
Decrease to accrued other postretirement benefits									(106)
Curtailment loss(gain)									17
Settlement loss (gain)									$ 994