Shareholders' Equity - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023	Sep. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance						$ (9,550)
Other comprehensive income (loss) before reclassifications	[1]	$ (72)		$ (158)		(93)	$ (284)
Amounts reclassified from AOCI	[1]	(19)		127		(65)	425
Net current period Other comprehensive (loss)/income	[1]	(91)		(31)		(158)	141
Ending balance		(9,708)				(9,708)
Amortization of actuarial losses		(2)		155		(6)	469
Amortization of actuarial loss included in net periodic pension cost, tax		0		(45)		1	(129)
Loss on discontinuation of cash flow hedge due to forecasted transaction probable of not occurring, net							39
Loss on discontinuation of cash flow hedge due to forecasted transaction Probable of not occurring, tax							11
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	[1]	(9,617)		(11,487)		(9,550)	(11,659)
Ending balance	[1]	(9,708)		(11,518)		(9,708)	(11,518)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(157)		(157)		(167)	(105)
Other comprehensive income (loss) before reclassifications		(39)		(71)		(29)	(123)
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income		(39)		(71)		(29)	(123)
Ending balance		(196)		(228)		(196)	(228)
Unrealized Gains and Losses on Certain Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance				1			1
Other comprehensive income (loss) before reclassifications		1		(2)		1	(2)
Amounts reclassified from AOCI
Net current period Other comprehensive (loss)/income		1		(2)		1	(2)
Ending balance		1		(1)		1	(1)
Unrealized Gains and Losses on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(51)		(38)		(24)	6
Other comprehensive income (loss) before reclassifications		(35)		(83)		(60)	(157)
Amounts reclassified from AOCI		4		(6)		2	24
Net current period Other comprehensive (loss)/income		(31)		(89)		(58)	(133)
Ending balance		(82)		(127)		(82)	(127)
Defined Benefit Pension Plans & Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(9,409)		(11,293)		(9,359)	(11,561)
Other comprehensive income (loss) before reclassifications		1		(2)		(5)	(2)
Amounts reclassified from AOCI		(23)	[2]	133	[2]	(67)	401
Net current period Other comprehensive (loss)/income		(22)		131		(72)	399
Ending balance		$ (9,431)		$ (11,162)		$ (9,431)	$ (11,162)

[1] Net of tax.

[2] Primarily relates to amortization of actuarial losses for the nine and three months ended September 30, 2022 totaling $469 and $155 (net of tax of ($129) and ($45)), which are included in the net periodic pension cost.