Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Uncertainties [Abstract]
Balance at January 1		$ 1,225	$ 1,347	$ 1,619
Additions for tax positions related to the current year		110	125	131
Additions for tax positions of prior years		282	323	73
Reductions for tax positions of prior years		(49)	(83)	(101)
Settlements		(110)	(48)	(375)
Separation of Carrier and Otis	$ (439)	0	(439)	0
Balance at December 31		1,458	1,225	1,347
Gross interest expense related to unrecognized tax benefits		39	50	57
Total accrued interest balance at December 31	$ 165	$ 165	$ 141	$ 249