Fair Value Measurements (Fair Value Hierarchy Classification) (Details) (USD $)
In Millions, unless otherwise specified
 9 Months Ended 15 Months Ended 9 Months Ended
Sep. 30, 2014
Estimate of Fair Value, Fair Value Disclosure [Member]
Dec. 31, 2013
Estimate of Fair Value, Fair Value Disclosure [Member]
Sep. 30, 2014
Estimate of Fair Value, Fair Value Disclosure [Member]
Quoted price in active markets (Level 1) [Member]
Sep. 30, 2014
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Inputs, Level 2 [Member]
Sep. 30, 2014
Estimate of Fair Value, Fair Value Disclosure [Member]
Unobservable inputs (Level 3) [Member]
Sep. 30, 2014
Portion at Other than Fair Value Measurement [Member]
Dec. 31, 2013
Portion at Other than Fair Value Measurement [Member]
Sep. 30, 2014
Fair Value, Measurements, Recurring [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Sep. 30, 2014
Fair Value, Measurements, Recurring [Member]
Quoted price in active markets (Level 1) [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Quoted price in active markets (Level 1) [Member]
Sep. 30, 2014
Fair Value, Measurements, Recurring [Member]
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Fair Value, Inputs, Level 2 [Member]
Sep. 30, 2014
Fair Value, Measurements, Recurring [Member]
Unobservable inputs (Level 3) [Member]
Dec. 31, 2013
Fair Value, Measurements, Recurring [Member]
Unobservable inputs (Level 3) [Member]
Sep. 30, 2014
Fair Value, Measurements, Nonrecurring [Member]
Dec. 31, 2013
Fair Value, Measurements, Nonrecurring [Member]
Sep. 30, 2014
Fair Value, Measurements, Nonrecurring [Member]
Quoted price in active markets (Level 1) [Member]
Dec. 31, 2013
Fair Value, Measurements, Nonrecurring [Member]
Quoted price in active markets (Level 1) [Member]
Sep. 30, 2014
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Inputs, Level 2 [Member]
Dec. 31, 2013
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Inputs, Level 2 [Member]
Sep. 30, 2014
Fair Value, Measurements, Nonrecurring [Member]
Unobservable inputs (Level 3) [Member]
Dec. 31, 2013
Fair Value, Measurements, Nonrecurring [Member]
Unobservable inputs (Level 3) [Member]
Sep. 30, 2014
Pratt and Whitney [Member]
Sep. 30, 2013
Pratt and Whitney [Member]
Sep. 30, 2014
Pratt and Whitney [Member]
Sep. 30, 2014
UTC Climate, Controls and Security [Member]
Sep. 30, 2013
UTC Climate, Controls and Security [Member]
Sep. 30, 2014
Sikorsky [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]                                                          
Equity Method Investment, Other than Temporary Impairment                                                 $ 25       $ 28
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain                                               48   23      
Available-for-sale securities               863 988 863 988 0 0 0 0                            
Derivative Assets               100 90 0 0 100 90 0 0                            
Derivative Liabilities               (217) (157) 0 0 (217) (157) 0 0                            
Business Dispositions                               44 66 0 0 44 66 0 0            
Long-term receivables 954 586 0 954 0 1,016 655                                            
Customer financing notes receivable 262 366 0 262 0 270 394                                            
Short Term borrowings (347) (388) 0 (135) (212) (347) (388)                                            
Long-term debt (excluding capitalized leases) (21,992) (21,525) 0 (21,644) (348) (19,614) (19,807)                                            
Long-term liabilities (268) (253) 0 (268) 0 (294) (283)                                            
Gain (Loss) on Disposition of Business                                                 $ 193   $ 30 $ 38