Liabilities, Commitments and Contingencies - Narrative (Details) $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2025 USD ($) aircraft lot	Sep. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) aircraft	Sep. 30, 2018 USD ($) aircraft	Sep. 30, 2025 USD ($) aircraft lot	Sep. 30, 2024 USD ($)	Dec. 31, 2024 USD ($) aircraft	Jun. 30, 2025 aircraft	Dec. 31, 2018 USD ($) aircraft simulator	Dec. 31, 2011 lot tanker aircraft
Commitments And Contingencies [Line Items]
Environmental loss contingency, operation and maintenance period, maximum					30 years
Loss contingency, range of possible loss, portion not accrued	$ 1,175				$ 1,175		$ 1,002
Contingent liabilities on outstanding letters of credit agreements and surety bonds	2,864				2,864		2,991
Supplier finance program, obligation	1,919				1,919		2,703
Increase (decrease) in earnings from operations due to change in accounting estimate	(206)	$ (2,622)			(544)	$ (4,322)
Number of annual production lot | lot										13
VC-25B
Commitments And Contingencies [Line Items]
Contract value	$ 4,000				$ 4,000
Number of commercial aircraft | aircraft	2				2
Increase (decrease) in earnings from operations due to change in accounting estimate							(379)
KC-46A Tanker
Commitments And Contingencies [Line Items]
Contract value	$ 29,000				$ 29,000
Increase (decrease) in earnings from operations due to change in accounting estimate					$ (149)		(2,002)
Number of generation aerial refueling tanker | tanker										4
Number of aircraft | aircraft	154				154					179
Number of low rate initial production lot | lot	11				11
MQ-25
Commitments And Contingencies [Line Items]
Contract value				$ 890
Increase (decrease) in earnings from operations due to change in accounting estimate				$ (291)			$ (339)
Number of aircraft | aircraft				7
Cost-type contract modification, awarded amount			$ 657
Number of additional test aircraft | aircraft			2
T-7A EMD
Commitments And Contingencies [Line Items]
Contract value									$ 860
Number of aircraft | aircraft							5	4	5
Number of simulator | simulator									7
T-7A EMD and Production
Commitments And Contingencies [Line Items]
Increase (decrease) in earnings from operations due to change in accounting estimate							$ (1,770)
T-7A Production
Commitments And Contingencies [Line Items]
Number of aircraft | aircraft								342
Commercial Crew
Commitments And Contingencies [Line Items]
Increase (decrease) in earnings from operations due to change in accounting estimate							(523)
Minimum | Supplier Finance Program, Majority of Amounts Payable
Commitments And Contingencies [Line Items]
Supplier finance program, payment timing, period	30 days				30 days
Maximum | Supplier Finance Program, Majority of Amounts Payable
Commitments And Contingencies [Line Items]
Supplier finance program, payment timing, period	90 days				90 days
Commercial Aircraft Commitments | Total Contractual Trade-In Commitment
Commitments And Contingencies [Line Items]
Other commitment	$ 1,332				$ 1,332		1,393
Commercial Aircraft Commitments | Net Amounts Payable to Customers Related to Probable Contractual Trade-In Commitments
Commitments And Contingencies [Line Items]
Other commitment	67				67		275
Commercial Aircraft Commitments | Fair Value of Trade in Value of Aircraft
Commitments And Contingencies [Line Items]
Other commitment	63				63		270
Financing Commitment
Commitments And Contingencies [Line Items]
Other commitment	15,460				15,460		$ 17,124
Financing Commitment | External Credit Rating, Non Investment Grade
Commitments And Contingencies [Line Items]
Other commitment	12,131				12,131
Joint Venture
Commitments And Contingencies [Line Items]
Other commitment	$ 269				$ 269
Other commitment, period	7 years				7 years
2023
Commitments And Contingencies [Line Items]
Changes in estimates					$ 55
Contingent on Customer Negotiations
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	$ 87				87
Alaska Airlines 737-9 Accident and 737-9 Grounding
Commitments And Contingencies [Line Items]
Revenue from contract with customer, excluding assessed tax			$ 443
Capitalized Precontract Costs | KC-46A Tanker
Commitments And Contingencies [Line Items]
Capitalized precontract costs	99				99
Capitalized Precontract Costs | T-7A Production
Commitments And Contingencies [Line Items]
Capitalized precontract costs	333				333
Capitalized Precontract Costs | Commercial Crew
Commitments And Contingencies [Line Items]
Capitalized precontract costs	407				407
Potential Termination Liabilities | KC-46A Tanker
Commitments And Contingencies [Line Items]
Capitalized precontract costs	170				170
Potential Termination Liabilities | T-7A Production
Commitments And Contingencies [Line Items]
Capitalized precontract costs	849				849
Potential Termination Liabilities | Commercial Crew
Commitments And Contingencies [Line Items]
Capitalized precontract costs	$ 141				$ 141