Proposed Merger With GE Transportation (Details) - GE Transportation - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Jul. 18, 2018
Scenario Forecast
Business Acquisition [Line Items]
Cash payment for acquisition	$ 2,900
Outstanding shares retained (as a percent)	49.90%
Equity issued in acquisition	$ 10,184
Business combination, consideration transferred	$ 13,500
Scenario Forecast | GE and Pre-Merger Holders
Business Acquisition [Line Items]
Outstanding shares transferred (as a percent)	50.10%
Scenario Forecast | General Electric Company
Business Acquisition [Line Items]
Outstanding shares transferred (as a percent)	9.90%
Period for reverting shares	2 years
Cash to be received	$ 3,370
Subsequent Event
Business Acquisition [Line Items]
Closing sale price (in dollars per share)		$ 103.85