Segment Financial Data (Narrative) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
UTC Building and Industrial Systems [Member]
Segment Reporting Information [Line Items]
Effective Date of Announcement of Changes in Organizational Structure	September 23, 2013
Auxiliary Power Unit (APU) [Member]
Segment Reporting Information [Line Items]
Business Acquisition Revenue Reported By Acquired Entity For Current Year	$ 600
Effective Date of Announcement of Changes in Organizational Structure	July 1, 2012