Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	$ 3,400		$ 3,400
Loss Contingency, Range of Possible Loss, Portion Not Accrued	1,057		1,057		$ 1,095
Letters of Credit Outstanding, Amount	3,885		3,885		4,238
Cumulative Scenario [Member]
Commitments And Contingencies [Line Items]
Abnormal Production cost.			4,600
Lower Customer Delivery Payments
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	1,300		1,300
Cash Payments To Customers
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	1,000		1,000
Customer Concessions
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	200		200
Contingent On Customer Negotiations
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	900		900
Within Current fiscal Year [Member]
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	200		200
Within Next fiscal Year [Member]
Commitments And Contingencies [Line Items]
737 MAX customer concessions and other considerations liability	700		700
Financing Commitment
Commitments And Contingencies [Line Items]
Other Commitment	13,311		13,311		11,512
Financing Commitment | External Credit Rating, Non Investment Grade
Commitments And Contingencies [Line Items]
Other Commitment	13,189		13,189
Joint venture
Commitments And Contingencies [Line Items]
Other Commitment	256		256
Total Contractual Trade-In Commitment | Commercial Aircraft Commitments
Commitments And Contingencies [Line Items]
Other Commitment	685		685		950
Net Amounts Payable to Customers Related to Probable Contractual Trade-In Commitments | Commercial Aircraft Commitments
Commitments And Contingencies [Line Items]
Other Commitment	269		269		599
Fair Value of Trade In Value of Aircraft | Commercial Aircraft Commitments
Commitments And Contingencies [Line Items]
Other Commitment	269		269		580
KC-46A Tanker
Commitments And Contingencies [Line Items]
Contract Value	19,000		19,000
KC-46A Tanker | Capitalized Precontract Costs
Commitments And Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	252		252
KC-46A Tanker | Potential Termination Liabilities
Commitments And Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	305		305
B-737
Commitments And Contingencies [Line Items]
Abnormal Production cost.			1,501		2,567
737 MAX customer concessions and other considerations liability	3,443	$ 5,981	3,443	$ 5,981	$ 5,537	$ 7,389
737 MAX Storage, Pilot Training and Software Updates [Member]
Commitments And Contingencies [Line Items]
Additional expenses as a result of the 737 MAX grounding	$ 33	$ 118	$ 136	$ 239