Stockholders' Equity - Schedule of Changes in Balance of Accumulated Other Comprehensive Loss, Net of Income Taxes (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 6,333	$ 6,835	$ 9,266
Other comprehensive income (loss) before reclassifications	226	236	(666)
Amounts reclassified from AOCL
Amounts reclassified from AOCL	684	115	(114)
Other comprehensive income (loss), net of tax	910	351	(780)
Ending balance	6,721	6,333	6,835
Non-cash, non-operating pension settlement charge	479
Non-cash, non-operating pension settlement charge, after tax	$ 377
Non-cash, non-operating pension settlement charge, per share, after tax (in dollars per share)	$ 1.63
Retirement Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ (8,288)	(8,704)	(7,866)
Other comprehensive income (loss) before reclassifications	99	340	(689)
Amounts reclassified from AOCL
Amounts reclassified from AOCL	634	76	(149)
Other comprehensive income (loss), net of tax	733	416	(838)
Ending balance	(7,555)	(8,288)	(8,704)
AOCI related to retirement benefit plans, tax benefit	2,000	2,200	2,300
Other, net
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(164)	(99)	(157)
Other comprehensive income (loss) before reclassifications	127	(104)	23
Amounts reclassified from AOCL
Amounts reclassified from AOCL	50	39	35
Other comprehensive income (loss), net of tax	177	(65)	58
Ending balance	13	(164)	(99)
AOCL
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(8,452)	(8,803)	(8,023)
Amounts reclassified from AOCL
Ending balance	(7,542)	(8,452)	(8,803)
Recognition of settlement loss
Amounts reclassified from AOCL
Amounts reclassified from AOCL	377
Recognition of net actuarial losses
Amounts reclassified from AOCL
Amounts reclassified from AOCL	218	188	116
Amortization of net prior service costs
Amounts reclassified from AOCL
Amounts reclassified from AOCL	39	(112)	(265)
Other
Amounts reclassified from AOCL
Amounts reclassified from AOCL	$ 50	$ 39	$ 35