Revenue from Contracts With Customers - Performance obligations (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) contract
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term	1 year
Aerospace
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 2,476
Number of types of long-term sales contracts utilized | contract	2
Aerospace | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period in which remaining performance obligations expect to be satisfied and revenue recognized	12 months
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 1,409
Aerospace | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Period in which remaining performance obligations expect to be satisfied and revenue recognized	0 months
Sales expected to be recognized on multi-year contracts in place as of the end of the period	$ 1,067
Aerospace | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Payment term	1 year