Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		$ 10,016
Reclassification of tax effects per ASU 2018-02		(1,466)	$ (1,764)
Stockholders' equity attributable to parent, ending balance		9,520	10,016
Foreign currency translation [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		(987)	(489)	$ (400)
Other comprehensive income/(loss) before reclassifications		171	(498)	(133)
Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)		0	0	44	[1]
Net other comprehensive income/(loss)		171	(498)	(89)
Stockholders' equity attributable to parent, ending balance		(816)	(987)	(489)
Derivative instruments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance	[2]	9	11	9
Other comprehensive income/(loss) before reclassifications	[2]	2	(3)	9
Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)	[2]	0	1	(7)	[1]
Net other comprehensive income/(loss)	[2]	2	(2)	2
Stockholders' equity attributable to parent, ending balance	[2]	11	9	11
Defined pension and post-retirement benefit costs [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance	[3]	(1,643)	(1,708)	(1,968)
Other comprehensive income/(loss) before reclassifications	[3]	(444)	41	191
Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)	[3]	36	24	69	[1]
Net other comprehensive income/(loss)	[3]	(408)	65	260
Stockholders' equity attributable to parent, ending balance	[3]	(2,051)	(1,643)	(1,708)
Total [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stockholders' equity attributable to parent, beginning balance		(2,621)	(2,186)	(2,359)
Other comprehensive income/(loss) before reclassifications		(271)	(460)	67
Amounts reclassified from accumulated other comprehensive income/(loss) (net of income tax)		36	25	106	[1]
Net other comprehensive income/(loss)		(235)	(435)	173
Stockholders' equity attributable to parent, ending balance		$ (2,856)	$ (2,621)	$ (2,186)

[1] Includes reclassifications in 2021 of $44 million and $31 million of foreign currency translation and defined pension and post-retirement benefit costs, respectively, attributable to the gain on disposal of our Miller business (see Note 3 — Acquisitions and Divestitures). The net gain on disposal is included in Other income, net in the accompanying consolidated statements of comprehensive income.

[2] Reclassification adjustments from accumulated other comprehensive loss related to derivative instruments are included in Revenue and Salaries and benefits in the accompanying consolidated statements of comprehensive income. See Note 10 — Derivative Financial Instruments for additional details regarding the reclassification adjustments for the derivative settlements.

[3] Reclassification adjustments from accumulated other comprehensive loss are included in the computation of net periodic pension cost (see Note 13 — Retirement Benefits). These components are included in Other income, net in the accompanying consolidated statements of comprehensive income.