Variable Interest Entities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Total assets	$ 6,862	$ 5,510
Total liabilities	7,416	5,687
Current Assets
Variable Interest Entity [Line Items]
Total assets	5,423	3,976
Current Liabilities
Variable Interest Entity [Line Items]
Total liabilities	5,465	3,601
Noncurrent Assets
Variable Interest Entity [Line Items]
Total assets	1,439	1,534
Noncurrent Liabilities
Variable Interest Entity [Line Items]
Total liabilities	$ 1,951	$ 2,086
IAE International Aero Engines AG
Variable Interest Entity [Line Items]
Variable Interest Entity, Methodology for Determining Whether Entity is Primary Beneficiary	Pratt & Whitney holds a net 61% interest in the International Aero Engines AG (IAE) collaboration with MTU Aero Engines AG (MTU) and Japanese Aero Engines Corporation (JAEC) and a 49.5% ownership interest in IAE. IAE's business purpose is to coordinate the design, development, manufacturing and product support of the V2500 program through involvement with the collaborators.
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	49.50%
International Aero Engines LLC
Variable Interest Entity [Line Items]
Variable Interest Entity, Methodology for Determining Whether Entity is Primary Beneficiary	Additionally, Pratt & Whitney, JAEC and MTU are participants in International Aero Engines, LLC (IAE LLC), whose business purpose is to coordinate the design, development, manufacturing and product support for the PW1100G-JM engine for the Airbus A320neo aircraft and the PW1400G-JM engine for the Irkut MC21 aircraft. Pratt & Whitney holds a 59% net interest and a 59% ownership interest in IAE LLC. IAE and IAE LLC retain limited equity with the primary economics of the programs passed to the participants.
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	59.00%