Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 37,635	$ 46,058	$ 38,257
Other comprehensive income (loss), net of taxes	216	(393)	(339)
Ending balance	46,372	37,635	46,058
Derivatives
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(24)	73	144
Other comprehensive income (loss) before reclassification adjustments, pretax	508	114	684
Tax	(109)	(24)	(143)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	399	90	541
Reclassification adjustments, pretax	(168)	(237)	(775)
Tax	35	50	163
Reclassification adjustments, net of taxes	(133)	(187)	(612)
Other comprehensive income (loss), net of taxes	266	(97)	(71)
Ending balance	242	(24)	73
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,793)	(2,408)	(2,743)
Other comprehensive income (loss) before reclassification adjustments, pretax	647	(413)	70
Tax	(138)	86	12
Other comprehensive income (loss) before reclassification adjustments, net of taxes	509	(327)	82
Reclassification adjustments, pretax	(60)	(64)	329
Tax	17	6	(76)
Reclassification adjustments, net of taxes	(43)	(58)	253
Other comprehensive income (loss), net of taxes	466	(385)	335
Ending balance	(2,327)	(2,793)	(2,408)
Pension Plan Net Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI	3,000	3,500
Other Postretirement Benefit Plan Net Gain
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI	(400)	(500)
Pension Plan Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI	(174)	(141)
Other Postretirement Benefit Plan Prior Service Credit
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Pension and other postretirement benefit plans, net loss (gain) and prior service (credit) included in AOCI	(61)	(95)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,344)	(2,433)	(1,830)
Other comprehensive income (loss) before reclassification adjustments, pretax	(559)	17	(584)
Tax	23	63	(19)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	(536)	80	(603)
Reclassification adjustments, pretax	20	9	0
Tax	0	0	0
Reclassification adjustments, net of taxes	20	9	0
Other comprehensive income (loss), net of taxes	(516)	89	(603)
Ending balance	(2,860)	(2,344)	(2,433)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(5,161)	(4,768)	(4,429)
Other comprehensive income (loss) before reclassification adjustments, pretax	596	(282)	170
Tax	(224)	125	(150)
Other comprehensive income (loss) before reclassification adjustments, net of taxes	372	(157)	20
Reclassification adjustments, pretax	(208)	(292)	(446)
Tax	52	56	87
Reclassification adjustments, net of taxes	(156)	(236)	(359)
Other comprehensive income (loss), net of taxes	216	(393)	(339)
Ending balance	$ (4,945)	$ (5,161)	$ (4,768)