Commitments - Extended Warranty Liability (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Movement in deferred income
Amortization of deferred revenue	$ (5,100)	$ (9,500)
Current portion	12,264	12,264		$ 12,833
Noncurrent portion	3,965	3,965		$ 4,301
Extended Warranty
Movement in deferred income
Beginning Balance		425	$ 477
Revenue deferred for new extended warranty contracts		71	115
Amortization of deferred revenue		(154)	(169)
Other		(9)	(3)
Ending Balance	334	334	419
Current portion	171	171	196
Noncurrent portion	$ 163	$ 163	$ 223