Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Apr. 03, 2020
Net income attributable to common shareowners:
Net income attributable to common shareholders	$ 266	$ 317	$ 655	$ 898
Basic weighted average number of shares outstanding (in shares)	433,200,000	433,100,000	433,100,000	433,100,000
Stock awards and equity units (share equivalent)	1,900,000	0	1,000,000.0	0
Diluted weighted average number of shares outstanding (in shares)	435,100,000	433,100,000	434,100,000	433,100,000
Earnings Per Share of Common Stock:
Basic (in usd per share)	$ 0.61	$ 0.73	$ 1.51	$ 2.07
Diluted (in usd per share)	$ 0.61	$ 0.73	$ 1.51	$ 2.07
Antidilutive securities excluded from computation of EPS (in shares)	5,000,000.0		4,800,000
Separation | Otis | UTC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of shares distributed (in shares)					433,079,455
Share price (in dollars per share)					$ 0.01